Production of non-solid-stated polyester particles having solid-stated properties

ABSTRACT

A process for producing non-solid-stated polyester polymer particles having one or more properties similar to polyester polymer particles that have undergone solid-state processing.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a continuation application claiming priority to U.S.patent application Ser. No. 12/394,478, filed Feb. 27, 2009, whichclaims the benefit of the following U.S. Provisional Applications, Ser.Nos. 61/033,234, 61/033,239, 61/033,250, 61/033,254, and 61/033,257,each filed Mar. 3, 2008. Each of the above applications is incorporatedherein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to processes for makingpolyester polymer particles. In another aspect, the invention concernsprocesses for producing polyethylene terephthalate (PET) particles froma polyester polymer melt.

Typically, polyester polymers are formed into relatively small particlesthat are easily transportable and can be processed in bulk to produce avariety of polymer-containing end products. In general, the end products(e.g., water and soda bottles, food containers, consumer productcontainers, and the like) are formed by melting the polymer particlesand then shaping the melted polymer into the desired productconfiguration. For example, plastic beverage containers are often madeby melting polyethylene terephthalate (PET) particles in an extruder,shaping the melted PET into preforms, and then blow and/or stretch blowmolding the preforms into the final form.

Traditional (PET) polymer particulation processes generally include asolid-state polymerization (i.e., “solid-stating) step near the end ofthe process, wherein the particles undergo further polymerization toincrease the intrinsic viscosity (It.V.) to a desired level. Duringsolid-stating, the degree of crystallization and the onset-of-meltingtemperatures of the polymer particles also increase. One drawbackassociated with solid-state processing is the additional processingequipment required to solid-state the polymer particles and theassociated increased capital, operating, and maintenance costs.

Because solid-stating processes have been the predominate method ofmaking polyester polymer particles for years, much of the equipment usedto make end products from the polyester polymer particles (e.g.,extruders and molding equipment) are specifically designed to handlepolyester polymer pellets having the specific characteristics ofsolid-stated polyester polymer particles.

Thus, it is desirable to develop a process for producing polyesterpolymer particles that overcomes the high capital and operating costsassociated with solid-stating processes. In certain circumstances, itmay also be desirable for the improved particle production process toyield non-solid-stated polyester polymer particles that can be processedin conventional melting and molding equipment without modification tothe equipment. Therefore, it would be desirable to have anon-solid-stating particulation process that produces polyester polymerparticles having melting characteristics to consistently produce asimilar quality of molded parts, in conventional melting and moldingequipment without modification to the equipment, as those made fromconventional solid-stated particles.

SUMMARY

In one embodiment of the present invention, there is provided apolyester polymer production process comprising: (a) forming polyesterpolymer particles from a polyester polymer melt in a forming zone; (b)subsequent to step (a), quenching at least a portion of the particlesvia contact with a quench liquid in a quenching zone; (c) subsequent tostep (b), drying at least a portion of the particles in a drying zone;(d) subsequent to step (c), crystallizing at least a portion of theparticles in a crystallizing zone; and (e) subsequent to step (d),annealing at least a portion of the particles in an annealing zone,wherein at all points during and between steps (b) through (e) theaverage bulk temperature of the particles is maintained above 165° C.

In another embodiment of the present invention, there is provided apolyester polymer production process comprising: (a) forming initialpolyester polymer particles from a polymer melt having an intrinsicviscosity (It.V.) in the range of 0.70 dL/g to 1.2 dL/g when measured at25° C. in a 60/40 wt/wt phenol/tetrachloroethane solvent at a polymerconcentration of 0.50 g/100 ml, wherein the initial particles comprise ashell and a core, wherein the shell is cooler and more crystalline thanthe core, wherein at least a portion of the shell exhibitsstrain-induced crystallinity; (b) drying at least a portion of theinitial particles to thereby provide dried particles; (c) crystallizingat least a portion of the dried particles to thereby providecrystallized particles exhibiting both strain-induced crystallinity andspherulitic crystallinity; and (d) annealing at least a portion of thecrystallized particles to thereby provide annealed particles, whereinthe average bulk temperature of the initial particles and the driedparticles is maintained above the onset-of-melting temperature (T_(om))of the core, and wherein said polymer melt comprises a carboxylic acidcomponent and a hydroxyl component, wherein said carboxylic acidcomponent comprises at least 80 mole percent of the residues ofterephthalic acid and/or derivatives thereof, wherein said hydroxylcomponent comprises at least 80 mole percent of residues of ethyleneglycol.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified overview of the primary stages involved in aprocess for producing a polyester article, particularly illustrating themelt production stage, the particle production stage, and the articleproduction stage.

FIG. 2 is a simplified overview of the major steps involved in anon-solid-stating particle production stage configured in accordancewith one embodiment of the present invention, particularly setting forththe forming, quenching, drying, crystallizing, annealing, and coolingsteps of the particle production stage.

FIG. 3 is a schematic depiction of a specific equipment configurationcapable of carrying out the particle production steps depicted in FIG. 2in accordance with one embodiment of the present invention.

FIG. 4 is a side view of a centrifugal dryer for receiving a slurrycontaining polyester polymer particles and a quench liquid andseparating the quench liquid from the particles.

FIG. 5 is a sectional view of the centrifugal dryer of FIG. 4,particularly illustrating the tangential feeding of the slurring intothe dryer in a discharge direction generally in the direction ofrotation of the dryer rotor.

DETAILED DESCRIPTION

Referring initially to FIG. 1, a simplified overview of the primarystages of a polymer production system 10 is illustrated as generallycomprising a melt production zone 20, a particle production zone 22, andan article production zone 24. In general, a polyester polymer meltcreated in melt production zone 20 can be converted to a plurality ofpolymer particles in particle production zone 22. The particles can thenbe utilized to create a variety of polymer articles in articleproduction zone 24. Examples of polymer articles created in articleproduction zone 24 can include, but are not limited to, beveragebottles, food containers, consumer products bottles, films, fibers, andthe like.

In contrast to conventional polymer processing schemes, polymerproduction zone 22 of polymer production system 10 does not employ asolid-state polymerization step in one embodiment of the presentinvention. However, the polymer particles produced in non-solid-statingparticle production zone 22 can be used to produce molded articles withsimilar quality to those produced from traditional solid-stated polymerparticles. For example, in one embodiment, the molded articles producedfrom non-solid-stated polyester polymer particles exiting productionzone 22 can consistently exhibit clarity and structural integritysimilar to those produced using conventional solid-stated particles. Inorder to consistently produce quality molded articles, non-solid-statedpolyester polymer particles exiting production zone 22 need to exhibitappropriate melting characteristics.

In general, the melt behavior of the polyester polymer particles can becharacterized by thermal analysis with a differential scanningcalorimeter (DSC). Two components of melt behavior, melting point, alsoknown as the melting peak temperature, and onset-of-melt temperature,can be determined from a first DSC heating scan as described herein. Ingeneral, an 8±1 mg sample of the polymer made up of (1) a portion of asingle pellet or (2) a sample taken from several grams of cryogenicallyground pellets is heated from about 25° C. and to about 290° C. at aheating rate of 20° C./minute. The temperatures of the resultingendotherm peak(s) measured by the DSC correspond to the melting point(s)of the polymer particles. The onset-of-melt temperature is defined as,the temperature of the intercept of the baseline and the tangent line tothe low temperature side of the lowest peak melting endotherm.

For the testing in this application, the instrument(s) used is a TA'sQ2000 DSC with a Liquid Nitrogen Cooling System. A detailed procedurefollows.

1. Calibrate instrument according to its “User's Manual;” set the onsetof melting point of Indium and Lead at 156.6° C. and 327.47° C.,respectively, and heat of fusion of Indium at 28.71 J/g. Instrument ischecked weekly. Specimen of ground pellets (a quick single pass grind ona Wiley mill) of about 8.0 mg is scanned at a rate of 20° C./minute inthe presence of Nitrogen with a flow rate of 25 c.c./minute according tothe manufacturer's recommendation.

2. Tare a TA's aluminum pan and lid on a balance. Prepare a specimeninside the pan and weigh to about 8.0 mg. Cover the specimen with thelid.

3. Crimp the specimen between the pan and the lid on a TA's samplecrimper.

4. Prepare an empty crimped aluminum pan and lid as reference.

5. Place the specimen and reference pans in the DSC cell at roomtemperature.

6. After the DSC is cooled to −5° C. using a cooling tank-LNCS, it willstart to heat the specimen from −5° C. to 290° C. at a rate of 20°C./minute. Data will be saved for analysis.

DSC tests and resulting numbers described herein are conducted onparticles directly from the production process. In other words, theseparticles have not been subjected to additional thermal treatment.Specifically, these particles have not been subjected to the typicaldrying that is done to remove absorbed moisture prior to meltprocessing.

In one embodiment, the polyester polymer particles exhibit at least twomelting peaks. The low peak melting point is considered to be T_(m1a) asexplained further below, which is classified as a melting peak when thearea under the heating curve on a DSC first heating scan is at least theabsolute value of 1 J/g. If the area under the curve is less than 1Joule per gram (J/g), the uncertainty around whether a curve is truly apeak or not becomes too high. Moreover, one can determine that at leasttwo peaks exist when the endotherm(s) on a DSC scan exhibit at leastfour slopes, a first slope departing from a baseline, a second slope ofopposite sign from the first slope, and a third slope of opposite signfrom the second slope, and a fourth slope of opposite sign from thethird slope. The temperature locations of the peaks on each curve definethe melting points on that heating curve. For the purposes of computingthe area of the melting endotherms, the dividing point between two peaksis at the point between the peaks where the curve most closelyapproaches the baseline.

In this embodiment, if two or more peaks appear on a heating curve froma DSC first heating scan, then the first peak is the low peak meltingpoint T_(m1a), and the second peak is the high peak melting pointT_(m1b) such that T_(m1a)<T_(m1b). The low melting peak temperature canbe within a range of from 190° C. to 250° C., 190° C. to 245° C., 190°C. to 240° C., or 190° C. to 235° C. For example, the low melting peaktemperature can be greater than about 190° C., greater than about 195°C., greater than about 200° C., greater than about 205° C., greater thanabout 210° C., greater than about 215° C., greater than about 220° C.,greater than about 225° C., greater than about 230° C., or greater than235° C. and having a melting endotherm area with an absolute value of atleast about 1.0 J/g, at least 1.5 J/g, at least 2.0 J/g, at least 3.0J/g, at least 4.0 J/g, at least 8.0 J/g, or at least 16.0 J/g.

In one embodiment, the polyester polymer particles prepared according tothe present invention exhibit a single melting peak on a DSC firstheating scan having a peak temperature greater than about 220° C.,greater than about 225° C., greater than about 230° C., or greater than235° C. and having a melting endotherm area with an absolute value of atleast about 1 Joule per gram (J/g), at least about 1.5 J/g, at least 2.0J/g, at least 3.0 J/g, at least 4.0 J/g, at least 8.0 J/g, or at least16.0 J/g. If the area under the curve is less than 1 J/g, theuncertainty around whether a curve is truly a peak or not becomes toohigh. Further, actually performing a DSC analysis on the particles isnot necessary; rather, it is important only that the particles have thestated morphology. The stated analyses reveal the inherent properties ofthe polymer and need only be run to determine whether or not thepolyester polymer has or does not have the stated characteristics.

In some cases, particularly at low crystallinity due to crystallizationat relatively low temperatures and/or for short times, rearrangement ofcrystals can occur so rapidly in the DSC instrument during first heatingscans with scan rates of 20° C./min that the low melting point is notdetected. The low melting point can then be seen by increasing thetemperature ramp rate of the DSC instrument and using smaller samples.If the sample has a low melting peak, it will be seen at higher scanrates. Scan rates up to 500° C./min can be used. For solid-statedsamples that experienced relatively high temperatures for relativelylong times and exhibit only a single melting peak at a 20° C./min scanrate, no low melting peak is expected even at higher scan rates.

In some instances, depending on the specific thermal history of thepolyester resin pellets, the DSC heating curve obtained upon a DSC firstheating scan may exhibit an endothermic shoulder on the low-temperatureside of the principal endothermic melting peak rather than two separateand well defined melting peaks. A low-temperature endothermic shoulderof this type is defined by means of the curve obtained by taking thefirst derivative with respect to temperature of the original DSC curve.The shoulder appears as a peak in the derivative curve. With increasingtemperature, the derivative curve departs the baseline (at temperatureA) in the endothermic direction at a temperature greater than about 155°C., greater than 160° C., greater than about 165° C., greater than about170° C., greater than about 175° C., greater than about 180° C., greaterthan about 185° C., greater than about 190° C., greater than about 200°C., greater than about 205° C., greater than about 210° C., greater thanabout 215° C., or greater than 220° C., then achieves a maximumdisplacement from the baseline, and then reverses direction andapproaches or returns to the baseline but does not cross the baseline.At still higher temperatures, the derivative curve reverses direction(at temperature B) and again bends towards the endothermic direction,marking the beginning of the primary melting peak in the original DSCcurve. The heat of melting represented by the shoulder corresponds tothe area under the original DSC curve between temperatures A and B, andmust be greater than or equal to the absolute value of 1 J/g to beconsidered a true shoulder. Those skilled in the art recognize thatminor instrumental noise in the original DSC curve can appear ashigh-amplitude short-duration spikes in the derivative curve. Such noisecan be filtered out by requiring that all features in the derivativecurve spanning less than 5° C. be ignored.

Further, actually performing a DSC analysis on the particles is notnecessary; rather, it is important only that the particles have thestated morphology. The stated analyses reveal the inherent properties ofthe polymer and need only be run to determine whether or not thepolyester polymer has or does not have the stated characteristics.

In addition to exhibiting similar DSC curves and having similar meltingpoints, the polyester polymer particles created in non-solid-statingproduction zone 22 can also have an onset-of-melt temperature (T_(om))similar to the T_(om) of conventionally processed polymer particles. Inone embodiment, the polyester polymer particles can have anonset-of-melt temperature greater than about 165° C., greater than about170° C., greater than about 175° C., greater than about 180° C., greaterthan about 185° C., greater than about 190° C., greater than about 200°C., greater than about 205° C., greater than about 210° C., greater thanabout 215° C., or greater than 220° C.

While several of the properties of polyester polymer particles producedaccording to one embodiment of the present invention closely resemblethose of solid-stated polymer particles, the non-solid-stated particlesalso have several properties that distinguish them from solid-statedparticles. For example, in one embodiment, the polyester polymerparticles exiting particle production zone 22 can have an intrinsicviscosity (It.V.) that is within about 5 percent, within about 4percent, within about 3 percent, within about 2 percent, within about 1percent, or essentially the same as the It.V. of the polymer meltintroduced into particle production zone 22. This is in direct contrastto solid-stating processes, which typically increase the It.V. of theparticles by 10 percent or more.

In another embodiment, the non-solid-stated polyester polymer particlescan have a lower degree of crystallinity than polymer particles formedin a solid-stating process. Typically, solid-stated polymer particlescan have a degree of crystallinity greater than about 45 percent, whilethe polymer particles exiting production zone 22 can generally have adegree of crystallinity less than about 45 percent, less than about 44percent, less than about 42 percent, in the range of from about 34 toabout 42 percent, or about 36 to about 40 percent. Percent crystallinityas given here is calculated from DSC scan data.

In general, the crystallinity of the polymer particles can be determinedusing the above-described DSC first heating scan by first finding thedifference between the absolute value of the area of the meltingendotherm and the absolute value of the area of any crystallizationexotherm(s). This difference corresponds to the net heat of melting andcan generally be expressed in Joules/gram. The heat of melting of 100%crystalline PET can generally be taken to be 121 Joules/gram, so theweight fraction crystallinity of the pellet can be calculated as the netheat of melting divided by 121. The weight percent crystallinity is theweight fraction crystallinity expressed as a percentage.

In addition, because production zone 22 does not include a solid-statepolymerization step, the resulting polymer particles can havesignificantly lower amounts of polycondensation catalyst thanconventional solid-stated particles. Examples of polycondensationcatalysts can include, but are not limited to, compounds of titanium,germanium, tin, aluminum, and/or Group I and II metals. Theconcentration of polycondensation catalyst is reported as the parts permillion of metal atoms based on the weight of the polymer. The term“metal” does not imply a particular oxidation state. The polymerparticles exiting production zone 22 can comprise less than 75 parts permillion by weight (ppmw), less than about 50 ppmw, less than about 45ppmw, less than about 40 ppmw, less than about 35 ppmw, less than about30 ppmw, or less than 25 ppmw of one or more polycondensation catalystmetals.

In addition, because production zone 22 does not include a solid-statepolymerization step, the resulting polymer particles can be essentiallyfree of antimony compounds. The concentration of antimony catalyst isreported as the parts per million of metal antimony paste on the weightof the polymer. The term “metal” does not imply a particular oxidationstate. The polymer particles exiting production zone 22 can compriseless than 150 parts per million by weight (ppmw), less than about 100ppmw, less than about 75 ppmw, less than about 50 ppmw, less than about10 ppmw, less than about 8 ppmw, or less than 4 ppmw of antimony metal.

Referring again to polymer production system 10 illustrated in FIG. 1,melt production zone 20 can be at least partly defined by or within anyprocess capable of producing a polyester polymer melt from one or morestarting materials. The type and state of starting materials is notlimited; the polymer can undergo any melt history and can be in and/orcan have passed through any state prior to being converted to a polymermelt in melt production zone 20. For example, in one embodiment, thepolymer melt can be produced by melting solid polyester polymerparticles in an extruder. In another embodiment, the polymer meltexiting melt production zone 20 can be directly withdrawn from amelt-phase polymerization reactor. The polymer melt can comprise anycombination of virgin and/or scrap (i.e., recycle) polymer. The recycledpolymer can include post-consumer recycle material. In one embodiment,the polymer melt exiting melt production zone 20 can comprise at leastabout 65 weight percent, at least about 75 weight percent, at leastabout 80 weight percent, at least about 85 weight percent, at leastabout 90 weight percent, at least about 95 weight percent, orsubstantially all virgin polyester polymer.

In one embodiment of the present invention, melt production zone 20 cancomprise a melt-phase polymerization system capable of producing thepolymer melt from one or more polyester precursors (i.e., reactants orstarting materials). In one embodiment of the present invention, meltproduction facility can employ a two-stage melt-phase polymerizationprocess. In the first stage, two or more starting materials can react toform monomers and/or oligomers. In the second stage, the monomers and/oroligomers can react further to form the final polyester melt. If thereactants entering the first stage include acid end groups, such as, forexample, terephthalic or isophthalic acid, the first stage can bereferred to as an “esterification” stage. If the reactants entering meltproduction zone 20 have methyl end groups, such as, for example,dimethyl terephthalate or dimethyl isophthalate, the first stage can bereferred to as an “ester-exchange” or “transesterification” stage. Forsimplicity, the term “esterification” as used herein, includes bothesterification and ester exchange reactions.

In one embodiment, esterification of two or more starting materials canbe carried out in melt production zone 20 at a temperature in the rangeof from about 220° C. to about 305° C., about 235° C. to about 290° C.,or 245° C. to 285° C. and a pressure less than about 25 psig, or in therange of from about 1 psig to about 10 psig, or 2 psig to 5 psig. Ingeneral, the average chain length of the monomer and/or oligomersexiting the esterification stage can be less than about 25 units, orfrom about 1 to about 20 units, or from 5 to 15 units.

Examples of suitable melt-phase esterification systems that can beemployed in melt production zone 20 are described in U.S. Pat. Nos.6,861,494 and 6,906,164 and copending U.S. patent application Ser. No.11/635,411, the entire disclosures of which are incorporated herein byreference to the extent not inconsistent with the present disclosure.

The second stage of melt production zone 22 can be referred to as thepolycondensation stage. The polycondensation stage can be a single stepprocess or can be divided into a prepolycondensation (i.e.,prepolymerization or prepolymer stage) and one or more finalpolycondensation (i.e., finishing) steps. Generally, longer chainpolymers can be produced via a multi-step polycondensation process. Inone embodiment, the polycondensation stage can be carried out at atemperature in the range of from about 220° C. to about 320° C., about240° C. to about 300° C., or 270° C. to 295° C. and a sub-atmospheric(i.e., vacuum) pressure. When polycondensation is carried out in amulti-step process, the prepolymer reactor can convert the monomersand/or oligomers exiting the esterification stage into an oligomerhaving an average chain length in the range of from about 2 units toabout 40 units, about 5 units to about 35 units, or 10 units to 30units. The finisher reactor can then convert the oligomer into a finalpolymer melt having the desired chain length.

Examples of suitable melt-phase polymerization processes that can beemployed in melt production zone 20 are described in U.S. Pat. Nos.6,861,494 and 6,906,164, the entire disclosures of which areincorporated herein by reference to the extent not inconsistent with thepresent disclosure.

In one embodiment of the present invention, the polymer melt produced inmelt production zone 20 can have an intrinsic viscosity (It.V.) of atleast about 0.70 dL/g, at least about 0.71 dL/g, at least about 0.72dL/g, at least about 0.73 dL/g, at least about 0.74 dL/g, at least about0.75 dL/g, at least about 0.76 dL/g, at least about 0.77 dL/g, or atleast 0.78 dL/g. In another embodiment, the It.V. of the polymer meltcan be less than about 1.2 dL/g, less than about 1.15 dL/g, less thanabout 1.1 dL/g, or less than 1.05 dL/g. In another embodiment, thepolymer melt produced in melt production zone 20 can have an intrinsicviscosity (It.V.) in the range of 0.65 dL/g to 1.2 dL/g, in the range of0.65 dL/g to 1.15 dL/g, in the range of 0.65 dL/g to 1.1 dL/g, or in therange of 0.65 dL/g to 1.05 dL/g; in the range of 0.70 dL/g to 1.2 dL/g,in the range of 0.70 dL/g to 1.15 dL/g, in the range of 0.70 dL/g to 1.1dL/g, or in the range of 0.70 dL/g to 1.05 dL/g; in the range of 0.72dL/g to 1.2 dL/g, in the range of 0.72 dL/g to 1.15 dL/g, in the rangeof 0.72 dL/g to 1.1 dL/g, or in the range of 0.72 dL/g to 1.05 dL/g; inthe range of 0.74 dL/g to 1.2 dL/g, in the range of 0.74 dL/g to 1.15dL/g, in the range of 0.74 dL/g to 1.1 dL/g, or in the range of 0.74dL/g to 1.05 dL/g; in the range of 0.76 dL/g to 1.2 dL/g, in the rangeof 0.76 dL/g to 1.15 dL/g, in the range of 0.76 dL/g to 1.1 dL/g, or inthe range of 0.76 dL/g to 1.05 dL/g; or in the range of 0.78 dL/g to 1.2dL/g, in the range of 0.78 dL/g to 1.15 dL/g, in the range of 0.78 dL/gto 1.1 dL/g, or in the range of 0.78 dL/g to 1.05 dL/g.

In general, the intrinsic viscosity values described throughout thisdescription are set forth in dL/g units as calculated from the inherentviscosity measured at 25° C. in 60/40 wt/wt phenol/tetrachloroethane.The inherent viscosity is calculated from the measured solutionviscosity. The following equations describe such solution viscositymeasurements and subsequent calculations to Ih.V. and from Ih.V. toIt.V:

η_(inh)=[ln(t _(s) /t ₀)]/C

where

-   -   η_(inh)=Inherent viscosity at 25° C. at a polymer concentration        of 0.50 g/100 mL of 60% phenol and 40%        1,1,2,2-tetrachloroethane;    -   ln=Natural logarithm;    -   t_(s)=Sample flow time through a capillary tube;    -   t_(o)=Solvent-blank flow time through a capillary tube; and    -   C=Concentration of polymer in grams per 100 mL of solvent        (0.50%).

The intrinsic viscosity is the limiting value at infinite dilution ofthe specific viscosity of a polymer. It is defined by the followingequation:

$\eta_{int} = {{\lim\limits_{C->0}\left( {\eta_{sp}/C} \right)} = {\lim\limits_{C->0}\; {\ln \left( {\eta_{r}/C} \right)}}}$

where

-   -   η_(int)=Intrinsic viscosity;    -   η_(r)=Relative viscosity=t_(s)/t_(o)    -   η_(sp)=Specific viscosity=η_(r)−1

Instrument calibration involves replicate testing of a standardreference material and then applying appropriate mathematical equationsto produce the “accepted” Ih.V. values. In general, the calibrationfactor (CF) can be expressed according to the following equation:CF=Accepted Ih.V. of Reference Material/Average of ReplicateDeterminations. The corrected Ih.V. can then be calculated bymultiplying the calculated Ih.V. by the calibration factor. Finally, theintrinsic viscosity (It.V. or η_(int)) can then be estimated accordingto the Billmeyer equation:

η_(int)=0.5[e ^(0.5×Corrected Ih.V.)−1]+(0.75×Corrected Ih.V.)

In one embodiment of the present invention, the polymer melt produced inmelt production zone 20 and/or the polymer particles exiting particleproduction zone 22 can comprise alkylene terephthalate or alkylenenapthalate repeat units in the polymer chain. According to oneembodiment, the polyester polymer produced in melt production zone 20can comprise: (a) a carboxylic acid component comprising at least about80 mole percent, at least about 85 mole percent, at least about 90 molepercent, at least about 92 mole percent, or at least 96 mole percent ofthe residues of terephthalic acid, derivates of terephthalic acid,naphthalene-2,6-dicarboxylic acid, derivatives ofnaphthalene-2,6-dicarboxylic acid, or mixtures thereof, and (b) ahydroxyl component comprising at least about 80 mole percent, at leastabout 85 mole percent, at least about 90 mole percent, at least about 92mole percent, or at least 96 mole percent of the residues of ethyleneglycol or propane diol, wherein the percentages are based on 100 molepercent of carboxylic acid component residues and 100 mole percent ofhydroxyl component residues in the polyester polymer. Examples ofterephthalic acid and naphthalene dicarboxylic acid derivatives caninclude, but are not limited to, C₁ to C₄ dialkylterephthalates andC_(i) to C₄ dialkylnaphthalates, such as dimethylterephthalate and2,6-dimethylnaphthalate.

Typically, polyesters such as polyethylene terephthalate can be producedby first esterifying a diol (e.g., ethylene glycol) with a dicarboxylicacid (e.g., terephthalic acid in its free acid or C₁-C₄ dialkyl esterform) and then subsequently polycondensing the resulting ester monomerand/or oligomers to form the final polyester polymer. In one embodiment,more than one compound containing carboxylic acid group(s) orderivative(s) thereof can be esterified. All the compounds that enterthe process containing carboxylic acid group(s) or derivative(s) thereofthat become part of said polyester product comprise the “carboxylic acidcomponent,” and the individual mole percents of each of the compoundscontaining carboxylic acid group(s) or derivative(s) thereof sum to 100.The “residues” of the carboxylic acid components in the polymer meltand/or polymer pellets refers to the portion of the original componentsthat remain in the polyester product after polycondensation. In general,the mole percentages of hydroxyl and carboxylic acid residues in thepolymer products can be determined via proton NMR.

In one embodiment, the carboxylic acid component(s) can additionallyinclude one or more additional modifier carboxylic acid compounds, suchas, for example, monocarboxylic acid compounds, dicarboxylic acidcompounds, and compounds with a higher number of carboxylic acid groups.Examples of suitable modifier carboxylic acid compounds can include, butare not limited to, aromatic dicarboxylic acids having in the range offrom about 8 to about 14 carbon atoms, aliphatic dicarboxylic acidshaving in the range of from about 4 to about 12 carbon atoms, orcycloaliphatic dicarboxylic acids having in the range of from about 8 toabout 12 carbon atoms. More specific examples of modifier dicarboxylicacids can include phthalic acid; isophthalic acid;naphthalene-2,6-dicarboxylic acid; cyclohexane-1,4-dicarboxylic acid;cyclohexanediacetic acid; diphenyl-4,4′-dicarboxylic acid; succinicacid; glutaric acid; adipic acid; azelaic acid; and sebacic acid. Itshould be understood that use of the corresponding acid anhydrides,esters, and acid chlorides of these acids is included in the term“carboxylic acid”. It is also possible for tricarboxyl compounds andcompounds with a higher number of carboxylic acid groups to be employedas modifiers.

In another embodiment, the hydroxyl component of the present polyestercan include additional modifier mono-ols, diols, or other compounds withhigher numbers of hydroxyl groups. Examples of modifier hydroxylcompounds can include, but are not limited to, cycloaliphatic diolshaving in the range of from about 6 to about 20 carbon atoms and/oraliphatic diols having in the range of from about 3 to about 20 carbonatoms. More specific examples of such diols can include diethyleneglycol; triethylene glycol; 1,4-cyclohexanedimethanol; propane-1,3-diol;butane-1,4-diol; pentane-1,5-diol; hexane-1,6-diol;3-methylpentanediol-(2,4); 2-methylpentanediol-(1,4);2,2,4-trimethylpentane-diol-(1,3); 2,5-ethylhexanediol-(1,3);2,2-diethyl propane-diol-(1, 3); hexanediol-(1,3);1,4-di-(hydroxyethoxy)-benzene; 2,2-bis-(4-hydroxycyclohexyl)-propane;2,4-dihydroxy-1,1,3,3-tetramethyl-cyclobutane;2,2-bis-(3-hydroxyethoxyphenyl)-propane; and2,2-bis-(4-hydroxypropoxyphenyl)-propane.

Typically, the polymer melt exiting melt zone 20 illustrated in FIG. 1can have a temperature in the range of from about 255° C. to about 315°C., about 260° C. to about 310° C., or 265° C. to 305° C. and can betransported to particle production zone 22 by any mechanism known in theart. In one embodiment, the polymer melt is pumped via gear pump,extruder, or other suitable device to the inlet of particle productionzone 22, which will now be described in further detail with reference toFIG. 2.

Turning now to FIG. 2, an overview of the primary steps of particleproduction zone 22, configured according to one embodiment of thepresent invention, is presented. In general, particle production zone 22comprises a forming zone 30, a quenching zone 32, a drying zone 34, acrystallizing zone 36, an annealing zone 38, and a cooling zone 40.Polymer particles created in forming zone 30 can be contacted with aquench liquid in quenching zone 32 and can thereafter be dried in dryingzone 34. The resulting dried particles can then be crystallized andannealed in respective crystallizing and annealing zones 36 and 38before being cooled in cooling zone 40. Processing zones 30, 32, 34, 36,38, and 40 will now be described in more detail below, beginning withforming zone 30.

In forming zone 30, a plurality of polyester polymer particles can becreated from the polymer melt routed to particle production zone 22 frommelt production zone 20, as illustrated in FIG. 1. Forming zone 30 canbe defined by or within any system capable of producing polymerparticles from a polymer melt. In one embodiment, the molten polyesterpolymer having a temperature in the range of from about 265° C. to about315° C., about 275° C. to about 305° C., or 280° C. to 295° C., can bepassed by a gear pump or extruder through a die. As the formed polymerpasses through the diehead, it may be cut to thereby form a plurality ofinitial polymer particles, which can thereafter be transported toquenching zone 32, as shown in FIG. 2.

Quenching zone 32 can be defined by or within any system suitable forcontacting at least a portion of the initial polyester particles with aquench liquid to thereby provide cooled, quenched polymer particles.Typically, the quench liquid can have a temperature that is at leastabout 50° C., at least about 100° C. or at least 150° C. less than theaverage bulk temperature of the polymer immediately prior to contactwith the quench liquid. In one embodiment, the quench liquid cancomprise water and can have a temperature in the range of from about 40°C. to about 110° C., about 50° C. to about 100° C., or 70° C. to 95° C.Generally, the particles can have an average residence time in quenchingzone 32 of less than about 30 seconds, less than about 20 seconds, lessthan about 10 seconds, less than about 5 seconds, less than about 3seconds, or less than 2 seconds. The specific volume or volumetric flowrate of quench liquid required depends on a variety of factors (e.g.,plant production rate and configuration), but can generally besufficient to provide a particle slurry having a solids content in therange of from about 2 to about 50 weight percent, about 3 to about 45weight percent, or 4 to 40 weight percent.

In one embodiment of the present invention, quenching zone 32 andforming zone 30 can be configured such that the forming and quenching ofthe polyester polymer particles can be carried out substantiallysimultaneously. For example, in one embodiment, the polymer melt can becut as it passes through the diehead, which can be submerged in a quenchliquid to thereby provide a plurality of quenched particles. In general,at least a portion of the quenched particles can exhibit a cooler, morecrystalline zone near the exterior of the particle (i.e., a shell) and awarmer, relatively amorphous region near the particle center (i.e., acore). In one embodiment, at least a portion of the shell can exhibitstrain-induced crystallinity.

The presence of the strain-induced semicrystalline shell is easilydetected by use of microscopy. The existence of a shell is clear fromsimple observation of pellets using an optical or scanning electronmicroscope. In one embodiment, the shell is discontinuous and is notpresent on some portions of the pellet surface, and the edges of theshell are very evident in these areas. The strain-inducedsemicrystalline nature of the shell can be confirmed by observingpellets which have been thoroughly quenched immediately after cutting soas to prevent the spherulitic crystallization of the core. These pelletsare transparent to the eye and when observed with an optical microscopeusing unmodified light they appear to be completely amorphous. However,when observed in an optical microscope between crossed polarizers thepellet appearance is characterized by the colored patternscharacteristic of birefringence, indicating preferential orientation ofthe polymer chains. Also, the shell can be stripped from the core bymeans of aggressive mechanical abrasion and when these isolated shellsare observed in an optical microscope between crossed polarizers theyalso exhibit the colored patterns indicative of birefringence.Furthermore, when these isolated shells are heated in a DSC there islittle or no crystallization exotherm present upon heating but a largemelting endotherm is present, demonstrating that the shells weresubstantially crystalline prior to heating in the DSC. These resultsmake it clear to one skilled in the art that the shells are composed ofsemicrystalline polymer having a strain or orientation inducedcrystalline morphology. When this test method is applied to particlestaken from the quench zone, the strain induced crystallization of theshell is readily apparent. The same test methods can also be used on thefinal product. Spherulitic crystallinity of the core can be seen undercross polarizers as a Maltese cross pattern.

One skilled in the art will recognize that a temperature differencedescribed above between a zone near the exterior of the particle and aregion near the particle center is a dynamic phenomenon. For example, ifthe quenched particles remained in the quenched liquid for a sufficientamount of time, the exterior and center of each particle wouldequilibrate to a temperature that would match the quench liquid.

The average bulk temperature of the polyester particles can be measuredby taking a sample of at least 10 particles at any point in the process,inserting a temperature measurement device into the sample, and readingthe temperature within 30-60 seconds from the time the particles exitthe process. Alternatively, the sample temperature can be measured usingan IR pyrometer “gun” or other temperature measurement device. To ensurea representative temperature measurement of the particles in quenchingzone 32, the quench liquid should be removed from the particles prior tothe temperature measurement.

As illustrated in FIG. 2, the slurry of quenched particles exiting zone32 can then be routed to a drying zone 34, wherein at least a portion ofthe quench liquid can be separated from the particles. In oneembodiment, drying zone 34 can be capable of separating at least about80 weight percent, at least about 85 weight percent, at least about 90weight percent, at least about 95 weight percent, at least about 98weight percent, or at least 99 weight percent of the quench liquid fromthe polymer particles in less than about 1 minute, less than about 30seconds, less than about 20 seconds, less than about 10 seconds, lessthan about 5 seconds, less than about 3 seconds, or less than about 2seconds.

Drying zone 34 can be defined by or within any type of suitable particledryer. For example, in one embodiment, the dryer can be a thermal dryer.In a thermal dryer, at least a portion of the liquid removal from theparticles is accomplished via direct or indirect heat exchange with awarmed heat transfer medium. Examples of suitable thermal dryersinclude, but are not limited to, rotary dryers, flash dryers, fluidizedand vibrating fluidized bed dryers, paddle dryers, plate dryers, andspiral dryers. In another embodiment, the at least a portion of thedrying step carried out in drying zone 34 can be accomplished in amechanical dryer. In a mechanical dryer, liquid is separated from theparticles without the addition of a substantial amount of externalthermal energy. In general, mechanical dryers can require less thanabout 100, less than about 50, less than about 20, less than about 10,or less than 1 BTU of thermal energy per pound of polymer (BTU/lb) todry the polymer particles as described above. Examples of mechanicaldryers can include, but are not limited to, spray dryers and centrifugaldryers.

In one embodiment of the present invention, the total time that theparticles are immersed in the quench liquid (i.e., the quench time) canbe less than about 1 minute, less than about 30 seconds, less than about20 seconds, less than about 15 seconds, less than about 10 seconds, lessthan about 5 seconds, or less than 4 seconds. By minimizing the quenchtime, the average bulk temperature of the particles can be maintainedabove about than 150° C., 155° C., above about 160° C., above about 165°C., above about 170° C., above about 172° C., above about 175° C., above178° C. at all points during and between forming zone 30 and drying zone34. As a result, the dried particles introduced into crystallizing zone36 can have an average bulk temperature in the range of from about 155°C. to about 210° C., about 165° C. to about 205° C., about 170° C. toabout 200° C., or 175° C. to 195° C.

In general, crystallizing zone 36 can be operable to increase theparticle average bulk temperature so that the crystallized particlesexiting crystallizing zone 36 can have an average bulk temperature thatis at least about 5° C., at least about 10° C., at least about 12° C.,or at least 15° C. higher than the average bulk temperature of the driedparticles entering crystallizing zone 36. Typically, the average bulktemperature of the crystallized particles exiting crystallizing zone 36can be greater than about 155° C., greater than about 160° C., greaterthan about 165° C., greater than about 170° C., greater than about 172°C., greater than about 174° C., greater than about 176° C., greater thanabout 178° C., greater than about 180° C., greater than about 182° C.,greater than about 185° C., greater than about 187° C., greater thanabout 188° C., greater than about 189° C., greater than about 190° C.,or greater than about 192° C. In general, the average bulk temperatureof the crystallized particles exiting crystallizing zone 36 does notexceed about 220° C., about 210° C., or about 205° C. The pressure incrystallizing zone 36 can be less than about 15 psig, less than about 10psig, less than about 5 psig, less than about 2 psig, approximatelyatmospheric, or at a slight vacuum (i.e., in the range from about 700 mmHg to about 760 mm Hg, about 650 mm Hg to about 760 mm Hg, or about 600mm Hg to about 760 mm Hg).

Crystallizing zone 36 can be defined by or within any type ofcrystallizer capable of imparting a desired level of crystallinity tothe particles passing therethrough. In general, the crystallizer can bea single-stage or multi-stage crystallizer that employs one or moretypes of crystallization, such as, for example, thermal crystallizationor latent heat crystallization. A thermal crystallizer utilizes heatfrom an external source to further crystallize the polymer, while alatent heat crystallizer relies on the intrinsic energy of the particlesthemselves to promote crystallization. Both thermal and latent heatcrystallization can be carried out in either a gas-phase or aliquid-phase atmosphere. Generally, the average temperature of theatmosphere within a thermal crystallizer is at least about 1° C., atleast about 2° C., at least about 5° C., or at least 10° C. warmer thanthe average bulk temperature of the particles passing therethrough,while the average temperature of the atmosphere within a latent heatcrystallizer is at least about 1° C., at least about 2° C., at leastabout 5° C., or at least 10° C. cooler than the average bulk temperatureof the particles passing therethrough.

The specific configuration of the crystallizer associated withcrystallizing zone 36 can vary. In one embodiment, the crystallizer canbe a mechanically agitated crystallizer, while in another embodiment,the crystallizer can employ substantially no agitation. The crystallizercan be oriented in a generally horizontally, generally vertically, or atany angle therebetween. In one embodiment, the polymer particles have anaverage residence time in crystallizing zone 36 of less than about 30minutes, less than about 20 minutes, less than about 15 minutes, lessthan about 10 minutes, or less than 5 minutes. At least a portion of theresulting crystallized particles exiting crystallizing zone 36 cansubsequently be routed to annealing zone 38, as shown in FIG. 2.

Annealing zone 38 can be at least partially defined by or within anysystem capable of increasing the onset-of-melt temperature of thecrystallized particles without causing the particles to undergoadditional significant polymerization. In one embodiment of the presentinvention, the annealed particles exiting annealing zone 38 can have anonset-of-melt temperature and/or peak melting temperature that is atleast about 5° C., at least about 10° C., at least about 12° C., or atleast 15° C. greater than the onset-of-melt temperature and/or peakmelting temperature, respectively, of the crystallized particlesentering annealing zone 38. In general, the It.V. of the annealedparticles changes by less than about 5 percent, less than about 3percent, less than about 2 percent, or less than 1 percent as comparedto the It.V. of the crystallized particles entering annealing zone 38.

As noted above, crystallizing zone 36 can be defined by or within anytype of crystallizer capable of imparting a desired level ofcrystallinity to the particles passing therethrough and annealing zone38 can be at least partially defined by or within any system capable ofincreasing the onset-of-melt temperature of the crystallized particleswithout causing the particles to undergo additional significantpolymerization. One skilled in the art would recognize that someincrease in onset-of-melt temperature can occur in the crystallizingzone and some crystallization can occur in the annealing zone.Therefore, the crystallizing zone can be distinguished from theannealing zone in that more than half of the overall percentcrystallinity of the polymer particles leaving the annealing zone isobtained in the crystallizing zone. One skilled in the art will alsorecognize that a single piece of equipment can be part of thecrystallizing zone and the annealing zone. For example, in oneembodiment, particles with a low level of crystallinity enter a vesselforming a particle bed wherein a portion of the particle bed is in thecrystallizing zone and the remainder of the particle bed is in theannealing zone. These particles may enter the crystallizing zonedirectly from the drying zone without any mechanical agitations in thecrystallizing zone.

The average bulk temperature of the annealed particles withdrawn fromannealing zone 38 can be either greater than or less than the averagebulk temperature of the crystallized particles introduced at thereto.The small amount of heat of crystallization competes with the slightcooling caused by the optional stripping gas and normal heat loss to theenvironment. In one embodiment, the average bulk temperature of theannealed particles withdrawn from annealing zone 38 can be less than theaverage bulk temperature of the crystallized particles introducedthereto by an amount in the range of from about 0.5° C. to about 10° C.,about 1° C. to about 5° C., or 2° C. to 4° C. In another embodiment, theaverage bulk temperature of the annealed particles withdrawn fromannealing zone 38 can be greater than the average bulk temperature ofthe crystallized particles introduced thereto by an amount in the rangeof from about 0.5° C. to about 10° C., about 1° C. to about 5° C., or 2°C. to 4° C. In general, the average particle residence time in annealingzone 38 can be in the range of from about 1 hour to about 100 hours,about 5 hours to about 35 hours, about 8 hours to about 25 hours, or 10hours to 22 hours. Particle residence time in annealing zone 38 can alsobe 1 hour to 24 hours, 1 hour to 20 hours, 1 hour to 16 hours, 1 hour to12 hours, 1 hour to 8 hours, 1 hour to 6 hours, 1 hour to 4 hours, or 1hour to 2 hours; 2 hours to 24 hours, 2 hours to 20 hours, 2 hours to 16hours, 2 hours to 8 hours, 2 hours to 6 hours, or 2 hours to 4 hours; 4hours to 24 hours, 4 hours to 20 hours, 4 hours to 16 hours, 4 hours to12 hours, 4 hours to 8 hours, or 4 hours to 6 hours; 6 hours to 24hours, 6 hours to 20 hours, 6 hours to 16 hours, 6 hours to 12 hours, or6 hours to 8 hours; or 8 hours to 24 hours, 8 hours to 20 hours, 8 hoursto 16 hours, or 8 hours to 12 hours. Annealing zone 38 can typically beoperated under a pressure of less than about 20 psig, or in the range offrom about 0 psig to about 10 psig, or about 0 psig to about 5 psig.

In one embodiment of the present invention, annealing zone 38 canadditionally comprise a stripping zone (not illustrated), wherein atleast a portion of the particles in annealing zone 38 can be contactedwith a stripping gas to thereby remove at least a portion of theresidual volatile components associated with the particles. Examples ofvolatile components removed in the stripping zone include, for example,acetaldehyde (AA) and other undesirable reaction byproducts. In general,the annealed particles exiting annealing zone 38 can comprise less thanabout 20 ppmw, less than 15 ppmw, less than 10 ppmw, or less than 5 ppmwof residual AA and other volatile components, as measured by ASTMF2013-00, entitled “Determination of Residual Acetaldehyde inPolyethylene Terephthalate Bottle Polymer Using an Automated StaticHead-Space Sampling Device and a Capillary GC with a Flame IonizationDetector”.

In general, the stripping gas may contact the particles co-currently orcounter-currently in a batchwise or continuous manner. Any type oramount of stripping gas can be used to remove the desired amount ofvolatile components from the polymer particles. Typically, the strippinggas can be a nitrogen-containing gas that is optionally dried prior tointroduction into the stripping zone.

In one embodiment, the stripping gas can comprise greater than about 75mole percent, greater than about 80 mole percent, greater than about 85mole percent, greater than about 90 mole percent, or greater than 95mole percent nitrogen, with the balance, if any, being typicalcomponents found in air such as oxygen, argon, and/or carbon dioxide.The temperature of the stripping gas entering annealing zone 38 is notparticularly limited. The temperature of the stripping gas enteringannealing zone 38 can generally be less than about 45° C., or can be inthe range of from about 0° C. to about 40° C. or in the range of 5° C.to 30° C. According to one embodiment, the ratio of the volumetric flowrate of the stripping gas to the mass of pellets in the stripping zoneof annealing zone 38 can be in the range of from about 0.01:1 to about1.0:1, about 0.05:1 to about 0.5:1, or 0.1:1 to 0.3:1 standard cubicfeet (SCF) of gas per pounds (lbs) of polymer particles.

According to one embodiment, contacting the particles in annealing zone38 with a stripping gas can be sufficient to remove a major portion ofthe residual acetaldehyde (AA) without adding one or more AA scavengersto the polymer melt and/or particles. In one embodiment, the strippingzone of annealing zone 38 can have an AA removal efficiency of at leastabout 75 percent, at least about 80 percent, at least about 90 percent,or at least 95 percent, wherein AA removal efficiency can be definedaccording to the following formula: (total mass of AA associated withthe particles entering the stripping zone−total mass of AA associatedwith particles exiting the stripping zone)/(total mass of AA associatedwith the particles entering the stripping zone), expressed as apercentage.

In one embodiment of the present invention, the stripped, at leastpartially annealed particles exiting the stripping zone of annealingzone 38 can comprise less than about 250 ppmw, less than about 150 ppmw,less than about 100 ppmw, less than about 75 ppmw, less than about 50ppmw, less than about 25 ppmw, less than about 20 ppmw, less than about15 ppmw, less than 10 ppmw, less than about 5 ppmw, or substantiallyfree of one or more AA scavengers. Examples of acetaldehyde scavengerscan include, but are not limited to, 2-aminobenzamide, any knownamino-terminated polyamides having a molecular weight of less than25,000 g/mol, or less than 20,000 g/mol, or less than 12,000 g/mol. Inone embodiment, the amino-terminated polyamides can be the reactionproducts of adipic acid with m-xylylene diamine thereby forming endgroups, which form chemically-bound ‘imines’ with AA and removing itfrom the polymer particles.

As described previously, in one embodiment, at least a portion of thequenched particles exiting quenching zone 32 comprise a crystallinepolymer shell that at least partially surrounds an amorphous, moltenpolymer core. As the particles are dried in zone 34, crystallized inzone 36, and/or annealed in zone 38, at least a portion of the amorphouscore can undergo spherulitic crystallization, thereby providing annealedparticles that can exhibit a shell at least partly formed bystrain-induced crystallization and a core at least partiallycharacterized by spherulitic crystallization.

In one embodiment of the present invention, the above-described particleproduction zone 22 can have substantially lower energy requirements thanconventional solid-state particulation processes. For example, in oneembodiment, the total amount of thermal energy required to operate oneor more of zones 30, 32, 34, 36, and/or 38 can be less than about 100BTU per pound of polymer (BTU/lb), less than about 75 BTU/lb, less thanabout 50 BTU/lb, less than 25 BTU/lb, less than 10 BTU/lb, or less than5 BTU/lb.

As shown in FIG. 2, at least a portion of the annealed particles can bewithdrawn from annealing zone 38 and can be routed to an optionalcooling zone 40. Cooling zone 40 can be at least partially definedwithin or by any process capable of reducing the average bulktemperature of the annealed particles. In one embodiment, the averagebulk temperature of the annealed particles entering cooling zone 40 canbe in the range of from about 170° C. to about 205° C., about 175° C. toabout 200° C., or about 180° C. to about 195° C. Cooling zone 40 canemploy one or more cooling devices operable to cool the annealedparticles by at least about 40° C., at least about 50° C., at leastabout 75° C., or at least 100° C. Examples of cooling devices caninclude, but are not limited to, air blowers, horizontal or verticalrotary paddles, vertical tube heat exchangers, plate heat exchangers, orany other device known in the art. Typically, the particles have anaverage residence time in cooling zone 40 of less than about 90 minutes,less than about 75 minutes, or less than about 60 minutes. The averagebulk temperature of the cooled particles exiting cooling zone 40 can bein the range of from about 40° C. to about 100° C., about 50° C. toabout 80° C., or 60° C. to 75° C.

In one embodiment, the cooled polyester polymer particles exitingcooling zone 40 comprise spheroidal polyester particles. Spheroidalparticles can be spherical, nearly spherical, oval, elliptical, orglobular in shape; spheroids may or may not have tails. In general,spheroidal particles are substantially, but imperfectly, spherical andcan be clearly distinguishable from slabs, cylinders, pastilles, cones,rods, or other, irregular shaped particles having one or more corners.Spheroidal particles have several distinguishing characteristics. Forexample, spheroids generally define a longitudinal axis, Y, and alateral axis, X, and the ratio of Y:X can typically be less than about 2or less than about 1.5.

In general, spheroids can be characterized according to the followingtest: when 10.0 g of pellets are placed near one edge of a smoothhorizontal steel plate in a grouping one pellet thick, and the plate issmoothly and gradually elevated at that edge to tilt the plate,spheroidal particles will roll from the plate such that no more than 0.5g of pellets remain on the plate when the plate first makes an angle of13 degrees with respect to the horizontal. In one embodiment, thespheroids have a peak mode in a roundness distribution less than 1.4,less than 1.3, or less than 1.2. The roundness of a spheroid is definedas perimeter²/(4π×area). “Perimeter” and “area” are defined in thecontext of a cross-sectional view of a spheroid.

In one embodiment, at least a portion of the cooled particles exitingcooling zone 40 can have a number average weight in the range of fromabout 0.60 to about 2.5 grams per 50 particles (g/50), about 1.0 toabout 2.0 g/50, or 1.4 to 1.8 g/50. The average particle size can be inthe range of from about 1 to about 8 mm, about 1.5 to about 6 mm, or 2to 5 mm. When the cooled particles comprise spheroidal particles, theaverage particle size can be defined as the average length of thelongitudinal axis, Y.

In one embodiment of the present invention, the It.V. of the polyesterparticles exiting cooling zone 40 can be at least 0.72 dL/g, at least0.75 dL/g, at least 0.78 dL/g, or at least 0.81 dL/g, and up to about1.2 dL/g, or 1.1 dL/g. In addition, the polyester polymer particles cancomprise the same carboxylic acid and hydroxyl components as the polymermelt introduced into particle production zone 22 as previouslydescribed.

Referring back to FIG. 1, at least a portion of the polymer particlesexiting particle production zone 22 can be routed to article productionzone 24 via any transportation mechanism known in the art. In oneembodiment, the polymer particles can be packaged into a container, suchas, for example, a storage silo, dryer hopper, or a shipping container.Particles packaged in a storage silo may be held for a period of time asthey await shipment from one location to another. Polymer particlespackaged in a dryer hopper can subsequently be fed to an extruder,wherein the particles can be melted and the corresponding polymer meltcan be routed to article production zone 24 for further processing.Examples of shipping containers can include, for example, a Gaylord box,a crate, a railcar, a trailer that can be attached to a truck, a drum,or a cargo hold on a ship, and particles packaged therein can betransported to one or more article production zones that are located inthe same general location, or, alternatively, in substantially differentlocations than particle production zone 22.

Article production zone 24 can be at least partially defined by orwithin any process capable of producing one or more types ofpolymer-containing articles from at least a portion of the polymerparticles produced in production zone 22. Examples of articles producedcan include, but are not limited to, beverage bottles, food containers,films, fibers, and other products. When the polymer particles are usedin bottle production, the polymer particles entering article productionzone 24 can be generally be melted and can thereafter molded into hollowpreforms or “parisons” via an injection molding process. Next, thepreforms can be blow molded into beverage bottles and other similarcontainers having a desired size and shape. Alternatively, or inaddition, one or more other articles (e.g., food containers, consumerproduct containers, films, and fibers) can be produced in articleproduction zone 24 according to any method known in the art.

Turning now to FIG. 3, a specific equipment configuration suitable forcarrying out the steps of particle production zone 22 describedpreviously with respect to FIG. 2 is presented. Particle productionsystem 122 illustrated in FIG. 3 generally comprises a cutter 130, aquench vessel 132, a centrifugal particle dryer 134, a gas-atmospherelatent heat crystallizer 136, an annealer 138, and a particle cooler140. In addition, the particle production system 122 depicted in FIG. 3includes a quench liquid recycle system 150 and a particle temperaturecontrol system 160, both of which will be described in detail shortly.

Turning now to the operation of the process configuration depicted inFIG. 3, polymer melt exiting a melt production zone (not shown) can berouted to an inlet of cutter 130, wherein the molten polymer can travelthrough a plurality of chambers 170 before being extruded through aseries of apertures 172. As the melt passes through the apertures 172,the polymer strand can immediately be cut via contact with a rotatingblade 174. The resulting initial polymer particles can then beinstantaneously transferred into quench vessel 132, wherein theparticles can be immersed in a quench liquid (e.g., water). As shown inFIG. 3, the resulting slurry, which can have a solids content in therange of from about 2 to about 50 weight percent, about 3 to about 45weight percent, or about 4 to about 40 weight percent, can exit an upperoutlet of quench vessel 132 and can thereafter enter a slurry conduit176.

In one embodiment, the residence time of the slurry in slurry conduit176 can be minimized in order to maximize the average bulk temperatureof the particles traveling therethrough. In one embodiment, the averageparticle residence time in slurry conduit can be less than about 10seconds, less than about 5 seconds, less than about 4 seconds, less thanabout 3 seconds, less than about 2 seconds, or less than 1 second. Oneway to minimize residence time is to minimize the overall flow path ofslurry conduit 176. By “flow path” it is meant the entire flow distancethat the slurry travels, including both horizontal and vertical pipedistances. In one embodiment, the overall flow path length of slurryconduit 176 can be less than about 50 feet, less than about 40 feet,less than about 30 feet, less than about 25 feet, less than about 20feet, less than about 10 feet, or less than 5 feet. Another way tominimize residence time is to maximize the flow velocity of the slurrypassing therethrough. In one embodiment, the slurry can have a flowvelocity greater than about 10 feet per second (ft/s), greater thanabout 20 ft/s, greater than about 25 ft/s, greater than about 30 ft/s,greater than about 35 ft/s, greater than about 40 ft/s, or greater than45 ft/s. This is in direct contrast to conventional slurry transportvelocities, which are generally less than about 8 feet per second.

As illustrated in FIG. 3, the particle slurry in slurry conduit 176 canthen be introduced into centrifugal dryer 134, which is illustrated ingreater detail in FIGS. 4 and 5. Turning now to FIG. 4, centrifugaldryer 134 is illustrated as generally comprising a slurry inlet 210, ahousing 212, a screen 214, an upright rotor 215 that comprises a rotorshaft 216 and a plurality of paddles 220, a rotational power source 218,a separated liquid outlet 222, and a dried particle outlet 224. Inaddition, slurry conduit 176 is illustrated as further comprising aslurry pump 204, a particle filter 206, and a liquid removal device 208.

As shown in FIG. 4, the particle slurry in conduit 176 can be passedthrough optional particle filter 206 prior to entering centrifugal dryer134. Particle filter 206 can define a slurry inlet 205, which cangenerally be positioned at a generally lower vertical elevation than aslurry outlet 207. In one embodiment, slurry entering slurry inlet 205can be pumped or otherwise pressured upwardly through particle filter206. In one embodiment, particle filter 206 can separate at least about60 percent, at least about 75 percent, at least about 80 percent, or atleast 90 percent of the total amount agglomerated chunks of particlesfrom the slurry stream in conduit 176. The resulting particle slurryexiting slurry outlet 207 can then be passed through an optional liquidremoval device 208, as shown in FIG. 4. In another embodiment (notshown), optional particle filter 206 can be located at the exit of dryer134. The dried particle feed can generally be positioned at a generallyhigher vertical elevation that the particle exit.

Optional liquid removal device 208 can be any device capable ofseparating a major portion of the liquid in which the particles areimmersed. In one embodiment, liquid removal device 208 can be operableto separate at least about 50 percent, at least about 65 percent, atleast about 75 percent, at least about 85 percent, or at least about 90percent of the liquid from the slurry thereby creating a concentratedslurry and a separated liquid stream. Typically, the concentrated slurrycan have a solids content in the range of from about 25 to about 99weight percent, about 40 to about 97 weight percent, or 75 to 95 weightpercent. Examples of suitable liquid removal devices can include, butare not limited to, an angularly oriented screen or other small-meshfilters. Although depicted as two separate units, in one embodiment (notshown), liquid removal device 208 and particle filter 206 can be asingle unit upstream of said dryer 134.

As shown in FIG. 4, the concentrated slurry exiting the slurry outlet209 of liquid removal device 208 and can subsequently be introduced intocentrifugal dryer 134. One embodiment of a specific slurry introductionsystem associated with centrifugal dryer 134 will be discussed infurther detail shortly with respect to FIG. 5. Turning first to theconfiguration of centrifugal dryer 134 illustrated in FIG. 4,centrifugal dryer 134 can comprise a generally cylindrical screen 214positioned inside of housing 212. The upright rotor 215 can bepositioned inside screen 214 and can be rotated about axis of rotation219 via a motor or other rotational power source 218. In one embodiment,the vertically and circumferentially spaced paddles 220 that extendoutwardly from rotor shaft 216 can extend from a vertical position justabove slurry inlet 210 to a vertical position just below dried particleoutlet 224 along rotor shaft 216.

As illustrated in FIG. 4, centrifugal dryer 134 can define a maximumhorizontal dimension (D) and a maximum vertical dimension (H). In oneembodiment, the ratio of H:D can be in the range of from about 1.1:1 toabout 20:1, about 1.5:1 to about 15:1, or about 2:1 to about 10:1.Generally, both D and H can be any length suitable for a particularfacility or application. In one embodiment, H can be in the range offrom about 0.5 to about 100 feet, about 2 to about 75 feet, or about 3to about 50 feet. Similarly, in another embodiment, D can be in therange of from about 0.25 to about 80 feet, about 0.5 to about 50 feet,or about 2 to about 35 feet. As illustrated in FIG. 4, slurry inlet 210can generally be positioned at a lower vertical elevation than driedparticle outlet 224, so that the particle/liquid mixture passesgenerally upwardly through centrifugal dryer 134.

Referring now to FIG. 5, a sectional view of centrifugal dryer 134 takenalong line 5-5 in FIG. 4 is presented. As shown in the embodimentdepicted in FIG. 5, slurry inlet 210 can be located at a position offsetfrom axis of rotation 219 by an offset distance (d). Typically, theratio of the offset distance d to the maximum horizontal dimension D ofcentrifugal dryer 134 can be less than about 0.45:1, less than about0.40:1, less than about 0.35:1, less than about 0.30:1, less than about0.25:1, less than about 0.20:1, or less than 0.15:1. This is in directcontrast to conventional centrifugal pellet dryers, which typicallyposition the slurry inlet directly in line the axis of rotation 219 ofthe upright rotor 215 (i.e., d=0).

The operation of centrifugal dryer 134 will now be described in moredetail, beginning with the introduction of slurry into slurry inlet 210.In one embodiment, the slurry discharged through slurry inlet 210 can beintroduced in a discharge direction that is generally in the samedirection of rotation of upright rotor 215. In another embodiment,slurry discharged through slurry inlet 210 can be discharged intocentrifugal dryer 134 generally tangentially to the inside of screen214, as shown in FIG. 5. Typically, the slurry can be discharged intocentrifugal dryer 134 at a slurry discharge speed, which can be lessthan about 75 percent, less than about 70 percent, less than about 65percent, or less than 55 percent of the speed of the tips of paddles 220(i.e., the tip speed). In general, the rotational speed of upright rotor215 can generally be at least about 850 revolutions per minute (rpm), atleast about 900 rpm, at least about 1,000 rpm, or at least 1,500 rpm.

Turning back to FIG. 4, as the particle slurry travels generallyupwardly through dryer 134, the centrifugal force associated withrotating paddles 220 forces the liquid/particle mixture outwardly towardscreen 214, which allows the liquid to pass through while retaining theparticles on its interior surface. The dried particles rotate in anascending route upwardly along the interior of screen 214, while theseparated liquid falls downwardly in the region between housing 212 andscreen 214. The liquid collects in the lower volume of the dryer and canbe removed via liquid outlet 222, while the dried particles can bewithdrawn in the upper region of dryer 134 via dried particle outlet224.

Turning back to FIG. 3, at least a portion of the dried particles canthereafter be transported to a gas-atmosphere latent heat crystallizer136. In one embodiment, crystallizer 136 can comprise a shaker deckcrystallizer defining a dried particle inlet 226 and a crystallizedparticle outlet 228. Typically, shaker deck crystallizers can behorizontally oriented and can comprise a vibrationally moveable surfaceoperable to transport at least a portion of the dried particles frominlet 226 to outlet 228. As the particles pass through crystallizer 136,at least a portion of the dried particles can undergo crystallization asdiscussed previously with respect to FIG. 2. As illustrated in FIG. 3,the crystallized particles exiting crystallized particle outlet 228 canthen be introduced into an annealer 138, which additionally employs anitrogen-containing stripping gas to remove at least a portion of theresidual AA and other volatile contaminants from the particles therein.

Annealer 138 can be any vessel suitable for containing a plurality ofparticles and, optionally, allowing a gas stream to pass therethrough.In one embodiment, annealer 138 comprises a crystallized particle inlet230, an annealed particle outlet 232, a stripping gas inlet 234, and astripping gas outlet 236. In one embodiment, stripping gas inlet 234 andannealed particle outlet 232 can be located at a lower verticalelevation than crystallized particle inlet 230 and stripping gas outlet236. Typically, stripping gas inlet 234 can be located at a verticalelevation corresponding to about 0.5 or about 0.25 the height of theparticle bed within annealer 138. As illustrated in FIG. 3, crystallizedparticles introduced near the upper portion of annealer 138 viacrystallized particle inlet move by gravity towards the lower portion ofannealer 138, while the stripping gas contacts the falling particles ina countercurrent manner. As the particles accumulate to thereby form aparticle bed, the bed slowly descends toward annealed particle outlet232. Generally, the bed height is not limited, but can be at least about50 percent, at least about 65 percent, or at least 75 percent of themaximum vertical distance (L) of annealer 138. In one embodiment,annealer 138 can have an aspect ratio (L:D) of at least about 2, atleast about 4, or at least about 6.

As shown in FIG. 3, the annealed particles withdrawn from annealedparticle outlet 232 of annealer 138 can subsequently be routed to cooler140, wherein at least a portion of the particles can be cooled asdescribed previously with respect to FIG. 2. Thereafter, the cooledparticles can be routed to article production zone 24 as shown in FIG.1, or otherwise stored or transported for subsequent processing andproduction.

Referring back to the separated liquid stream exiting liquid outlet 222of centrifugal dryer 134 illustrated in FIG. 3, at least a portion ofthe separated liquid stream can be routed to quench liquid recyclesystem 150, which is illustrated as generally comprising a quench liquidsurge tank 152, a recycle pump 154, and a quench cooler 156. In general,the separated liquid exiting centrifugal dryer 134 collects in quenchsurge tank 152. A recycle liquid stream withdrawn from a lower outlet ofsurge tank 152 can be routed to a suction port of recycle pump 154 priorto being discharged and routed through quench cooler 156. Typically, theseparated liquid discharged from recycle pump 154 can have a temperaturein the range of from about 80° C. to about 110° C., about 85° C. toabout 105° C., or about 90° C. to 100° C., and quench cooler 156 can beoperable to reduce the temperature of the liquid by at least about 35°C., at least about 40° C., at least about 45° C., or at least 50° C. Thecooled quench liquid exiting quench cooler 156 can then be routed toquench vessel 132 and can continue through the cycle as discussedpreviously.

In one embodiment of the present invention, particle production system122 can additionally comprise a particle temperature control system 160,which can generally be integrated with quench liquid recycle system 150to control the average bulk temperature of the particles duringproduction. In one embodiment, the average bulk temperature of theparticles can be maintained above at least about 155° C., at least about160° C., at least about 165° C., at least about 170° C., at least about175° C., or at least about 180° C. during all points of the particleproduction process from the introduction of the polymer melt into cutter130 to the withdrawal of annealed particles from annealer 138.

In one embodiment illustrated in FIG. 3, particle temperature controlsystem 160 generally comprises a downstream temperature indicator 162, adecision center 164, and a plurality of flow control valves 166 a-c. Ingeneral, downstream temperature indicator 162 measures a temperatureassociated with the dried and/or crystallized particles respectivelyexiting dryer 134 and/or crystallizer 136. In one embodiment, themeasured downstream temperature can be the particle average bulktemperature. In another embodiment, the measured downstream temperaturecan be a related downstream temperature, such as, for example, thetemperature of the atmosphere surrounding the particles, or any otherdownstream temperature.

Once the downstream temperature has been measured, temperature indicator162 transmits a signal to decision center 164, as illustrated by thedashed line in FIG. 3. In one embodiment, decision center 164 cancompare the measured temperature to a target temperature to determine adifference. In one embodiment, the target temperature may be anytemperature corresponding to a particle average bulk temperature in therange of from about 155° C. to about 215° C., about 170° C. to about210° C., or 180° C. to 195° C. By “corresponding to,” it is meant thatthe measured temperature is related to, but is not required to actuallybe, the particle average bulk temperature. In one embodiment, themeasured temperature can be, for example, the temperature of the fluidmedium surrounding the particles, which can be relatable to a certainparticle average bulk temperature via experimental data or some othertype of correlations.

Once decision center 164 has determined a difference between themeasured temperature and the target temperature, decision center 164 canadjust the time that the particles exiting cutter 130 are immersed inthe quench liquid. In general, if the determined difference is positive(i.e., the actual temperature is higher than the target temperature),decision center 164 may increase the contacting time between the quenchliquid and the particles. If the determined difference is negative(i.e., the actual temperature is lower than the target temperature),decision center 164 can reduce the contact time between the quenchliquid and the particles. In one embodiment, at least a portion of thecomparison and/or adjusting carried out in decision center 164 can bemanual (i.e., directly controlled by human intervention). In anotherembodiment, at least a portion of the comparison and/or adjustingcarried out in decision center 164 can be automatic (i.e., controlled byan automated control system).

Several methods exist for adjusting the contact time between the quenchliquid and the immersed particles and a few examples will be discussedwith respect to FIG. 3. In one embodiment, the quench contact time canbe adjusted by changing the speed of recycle pump 154. In anotherembodiment, quench contact time can be adjusted by changing thevolumetric flow rate of the quench liquid introduced into quench vessel132 and/or slurry conduit 176. In one embodiment, the volumetric flowrate of the quench liquid contacting the initial particles can bechanged by varying the amount of recycle quench liquid diverted backinto quench surge tank 152 by adjusting flow control valves 166 a and166 b.

In another alternative or additional embodiment, the difference betweenthe measured and target temperature can be minimized by adjusting thetemperature of the quench liquid. In one embodiment, the temperature ofthe quench liquid can be adjusted by changing the amount of quenchliquid by-passing quench cooler 156 by adjusting flow control valve 166c. In addition, additional heat exchangers (e.g., heaters and/orcoolers) can be added to quench recycle system 150 in order to furthercontrol the temperature of the quench liquid entering quench vessel 132.

Once decision center 164 has caused one or more adjustments to be made,indicator 162 can measure the downstream temperature again and theprocess described above can be repeated. In one embodiment, the steps ofmeasuring, comparing, and adjusting can be repeated until the differencebetween the target temperature and the measured temperature is less thanabout 10 percent, less than about 7 percent, less than about 5 percent,less than about 3 percent, or less than 1 percent of the targettemperature.

EXAMPLES

The examples are all resins of PET. C1 was manufactured to a target PETcomposition with 1.5 wt. % DEG and 2.7 wt. % IPA. All other exampleswere manufactured to target PET compositions with 1.5 wt. % DEG and 2.5wt. % IPA. The intrinsic viscosity target for each example was 0.84dL/g. Comparative Examples are denoted by the letter “C” before theexample number.

Example C1 was produced on a manufacturing line and is the only examplesubject to solid-state processing. All other examples were producedusing a melt-phase only process. In other words, all examples except C1were not solid-state polymerized. Example C2 was produced in asemi-works facility and the rest of the examples were produced on amanufacturing line.

A study was conducted comparing the solid stated resin, C1, melt phaseonly resin produced in the semiworks facility, C2, and melt phase onlyresin produced on a manufacturing line, Examples C3-C4 and 5-6. ExamplesC3-C4 and 5-6 were annealed during production at an exit temperature of172° C. for approximately 18 hours. The annealing temperature wasmeasured using a thermocouple inserted into pellets from the outflow ofthe annealer. Examples C4, 5, and 6 were subject to a secondaryannealing step in a tumbling dryer. The dryer set points and actualpellet temperatures are given in Table 1. The pellet temperature wasmeasured by taking a sample of pellets from the dryer in an insulatedcontainer and inserting a thermocouple into the pellets. The exampleswith the different processing histories had different low melting peaktemperatures.

TABLE 1 Secondary Annealing Conditions Oil Set Point Pellet Example TimeTemperature Temperature C4 5.0 hr 185° C. 160° C. 5 3.5 hr 200° C. 174°C. 6 2.0 hr 215° C. 194° C. 10 4.0 hr 230° C. 215° C.

Examples C1-C4 and 5-6 were formed into preforms on a Husky XL-300 PETequipped with a 100 mm screw. Standard preform production settings wouldtypically include a 555° F. barrel temperature set point, an 800 psiback pressure set point, and a 32 second injection molding cycle timeset point. In order to accentuate the number of bubble defects, a set ofbubble defects experiments were run with a 540° F. barrel temperatureset point in each zone, a 300 psi back pressure set point, and a 30second injection molding cycle time set point. Once the machine hadstabilized to these settings, 4 shots were collected every 15 minutesfor a total of 20 shots or 860 preforms for each example. The tests wererepeated with the same settings and the same number of preformscollected later in the day.

On the same day, in order to accentuate the number of preform unmeltdefects, a set of unmelt defects experiments were run with barreltemperature set points of 500° F., 515° F., 530° F., 540° F., 540° F.,and 540° F. across zones 1-6, respectively; a 300 psi back pressure setpoint; and a 24.5 second injection molding cycle time set point. Oncethe machine had stabilized to these settings, 4 shots were collectedevery 15 minutes for a total of 20 shots or 860 preforms for eachexample. The tests were repeated with the same settings and the samenumber of preforms collected later in the day.

Results of the bubble defects experiments and unmelt defects experimentsare shown in Table 2. Preforms were visually inspected for bubbledefects and unmelt defects. The percent bubble defects is the percent ofpreforms containing one or more bubble defects. The percent unmeltdefects is the percent of preforms containing one or more unmeltdefects.

Note that C1, which was solid-stated, only had one melting peaktemperature. Table 2 shows that the percent of preforms with at leastone bubble defect decreases with increasing low melting peaktemperature. Also, the percent of preforms with at least one unmeltdefect generally decreases with increasing low melting peak temperature.

An additional test was run on each sample for an indication of bubbledefects. The Examples were run through a Bekum Extrusion Blow MoldingMachine using a 100 mm die at 100% open and at a 540° F. flat barreltemperature set point. To maintain the diameter of the extrudate, air atapproximately 10 cubic feet per minute was applied. Material that wasgathered for each Example over a 15 second increment was weighed andvisually inspected for bubbles. The test was repeated three times atscrew rates of 20 revolutions per minute (rpm), 30 rpm, and 40 rpm foreach example. The result shown is the average bubbles per pound for allruns. For Example C1 only, the results are an average of severaldifferent sets of runs taken over several days. The number of bubbledefects per pound of extrudate is given in Table 2.

Example 6 showed an unusually high percent of unmelt defects and anunusually high number of bubbles per pound. Material was produced on amanufacturing line at higher annealing temperatures so as to have a lowmelting peak temperature of 214° C., Example 7. Note this material wasnot subjected to the secondary annealing step used for Examples C4, and5-6. Example 7 was subject to the same preform defect tests and bubbletest on the Bekum Machine as Examples C1-C4 and 5-6 above. The preformdata and number of bubble per pound are shown in Table 2.

Examples 8 and 9 are additional examples produced on the manufacturingline. Examples 8 and 9 were subject to the same preform defect tests andbubble test on the Bekum Machine as Examples C1-C4 and 5-6 above. Thelow melting peak temperature, preform defect data, and bubbles per poundare shown in Table 2.

Additional material from Example C2 was subjected to secondary annealingin a tumbling dryer at conditions shown in Table 1 as Example 10.Example 10 was subject to the same bubble test on the Bekum Machine asExamples C1-C4 and 5-6 above. Example 10 was not subject to the preformtests above.

TABLE 2 Preform Unmelt and Bubble Defects Low Peak Number of Melting %Unmelt % Bubble Bubbles per Example Temperature Defects Defects Pound C1245° C. 5.7 4.3 1.8 C2 189° C. 15.2 16.5 27 C3 189° C. 16.5 11.4 30 C4191° C. 15.8 10.0 25 5 197° C. 8.0 9.2 18 6 215° C. 14.1 7.1 13 7 214°C. 5.5 2.2 2.5 8 220° C. 6.9 0.5 2 9 231° C. 3.4 1.2 1 10 241° C. — — 0

Numerical Ranges

The present description uses numerical ranges to quantify certainparameters relating to the invention. It should be understood that whennumerical ranges are provided, such ranges are to be construed asproviding literal support for claim limitations that only recite thelower value of the range as well as claims limitation that only recitethe upper value of the range. For example, a disclosed numerical rangeof 10 to 100 provides literal support for a claim reciting “greater than10” (with no upper bounds) and a claim reciting “less than 100” (with nolower bounds).

DEFINITIONS

As used herein, the terms “a,” “an,” “the,” and “said” means one ormore.

As used herein, the term “and/or,” when used in a list of two or moreitems, means that any one of the listed items can be employed by itself,or any combination of two or more of the listed items can be employed.For example, if a composition is described as containing components A,B, and/or C, the composition can contain A alone; B alone; C alone; Aand B in combination; A and C in combination; B and C in combination; orA, B, and C in combination.

As used herein, the term “annealing” refers to any process thatincreases the onset-of-melt temperature of polyester polymer particleswithout or independent of further polycondensation.

As used herein, the term “average chain length” means the average numberof repeating units in the polymer. For a polyester, average chain lengthmeans the number of repeating units based on the acid and alcoholreaction. Average chain length is synonymous with the number averagedegree of polymerization (DP). The average chain length can bedetermined by various means known to those skilled in the art. Forexample, 1H-NMR can be used to directly determine the chain length basedupon end group analysis, and light scattering can be used to measure theweight average molecular weight with correlations used to determine thechain length. Chain length is often calculated based upon correlationswith gel permeation chromatography (GPC) measurements and/or viscositymeasurements.

As used herein, the term “bulk” refers to at least 10 isolatedparticles.

As used herein, the terms “comprising,” “comprises,” and “comprise” areopen-ended transition terms used to transition from a subject recitedbefore the term to one or more elements recited after the term, wherethe element or elements listed after the transition term are notnecessarily the only elements that make up the subject.

As used herein, the terms “containing,” “contains,” and “contain” havethe same open-ended meaning as “comprising,” “comprises,” and“comprise,” provided above.

As used herein, the term “esterification” refers to both esterificationand ester exchange reactions.

As used herein, the terms “having,” “has,” and “have” have the sameopen-ended meaning as “comprising,” “comprises,” and “comprise,”provided above.

As used herein, the terms “including,” “includes,” and “include” havethe same open-ended meaning as “comprising,” “comprises,” and“comprise,” provided above.

As used herein, the term “latent heat crystallization” refers tocrystallization processes wherein the crystallization environment ismaintained at or below the average bulk temperature of the particles.

As used herein, the term “liquid removal efficiency” can be expressedaccording to the following formula: (mass of liquid entering dryer withparticle slurry−mass of liquid exiting dryer with dried particles)/(massof liquid entering dryer with particle slurry), expressed as apercentage.

As used herein, the term “melt-phase” refers to the physical state of apolymer wherein at least a portion of the polymer is in the liquidphase.

As used herein, the term “non-solid-stated” refers to polyester polymerthat has not undergone solid stated processing as defined below.

As used herein, the terms “non-solid-stating,” and “non-solid-stateprocessing” refer to processes that do not significantly increase theintrinsic viscosity of a polyester polymer through solid-stateprocessing, as defined below.

As used herein, the terms “polyethylene terephthalate” and “PET” includePET homopolymers and PET copolymers.

As used herein, the terms “polyethylene terephthalate copolymer” and“PET copolymer” mean PET that has been modified by up to 20 mole percentwith one or more added comonomers. For example, the terms “polyethyleneterephthalate copolymer” and “PET copolymer” include PET modified withup to 20 mole percent isophthalic acid on a 100 mole percent carboxylicacid component basis. In another example, the terms “polyethyleneterephthalate copolymer” and “PET copolymer” include PET modified withup to 20 mole percent 1,4-cyclohexane dimethanol (CHDM) on a 100 molepercent diol component basis.

As used herein, the term “polyester” refers not only to traditionalpolyesters, but also includes polyester derivatives, such as, forexample, polyetheresters, polyester amides, and polyetherester amides.

As used herein, “predominately liquid” means more than 50 volume percentliquid.

As used herein, the term “residue” refers to the moiety that is theresulting product of the chemical species in a particular reactionscheme or subsequent formulation or chemical product, regardless ofwhether the moiety is actually obtained from the chemical species.

As used herein, the term “solid-stated” refers to polyester polymer thathas undergone solid stated processing as defined below.

As used herein, the terms “solid-stating” and “solid-state processing”refer to the process of significantly increasing the intrinsic viscosityof a polyester polymer by subjecting solid polyester polymer to furtherpolycondensation.

As used herein, the term “strain-induced crystallization” refers to theprocess of crystallizing a polyester polymer by applying strain to thepolymer.

As used herein, the term “stripping” refers to the process of flowing afluid through a plurality of polyester polymer particles to remove atleast a portion of the residual contaminants present therein.

As used herein, the term “thermal crystallization” refers tocrystallization processes wherein the crystallization environment ismaintained above the average bulk temperature of the particles.

NON-LIMITING LISTING OF EMBODIMENTS

In Embodiment A of the present invention, there is provided a polyesterpolymer production process comprising: (a) forming polyester polymerparticles from a polyester polymer melt in a forming zone; (b)subsequent to step (a), quenching at least a portion of the particlesvia contact with a quench liquid in a quenching zone; (c) subsequent tostep (b), drying at least a portion of the particles in a drying zone;(d) subsequent to step (c), crystallizing at least a portion of theparticles in a crystallizing zone; and (e) subsequent to step (d),annealing at least a portion of the particles in an annealing zone,wherein at all points during and between steps (b) through (e) theaverage bulk temperature of the particles is maintained above 165° C.

The process of Embodiment A, wherein the polyester polymer melt has anintrinsic viscosity (It.V.) in the range of 0.70 dL/g to 1.2 dL/g, 0.70dL/g to 1.1 dL/g, 0.72 dL/g to 1.2 dL/g, 0.72 dL/g to 1.1 dL/g, 0.76dL/g to 1.2 dL/g, 0.76 dL/g to 1.1 dL/g, 0.78 dL/g to 1.2 dL/g, or 0.78dL/g to 1.0 dL/g.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein said particles produced from saidannealing zone, when measured on a first heating DSC scan, have a lowmelting peak temperature greater than 190° C., and a melting endothermarea greater than the absolute value of 1 J/g, 2 J/g, 4 J/g, 8 J/g, or16 J/g.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein the It.V. of said particles produced fromsaid forming zone is within about 5 percent of the It.V. of saidparticles produced from said annealing zone.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein said particles produced from saidquenching zone comprise a shell and a core, wherein at least while saidparticles are within said quenching zone said shell is cooler and morecrystalline than said core.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein steps (b) and (c) are carried out in aperiod of time less than 1 minute.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein said particles produced from saidcrystallizing zone have an average bulk temperature greater than 180° C.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein said particles introduced into saidcrystallizing zone have an average bulk temperature in the range of fromabout 170° C. to about 210° C.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein said crystallizing is carried out in agas-phase atmosphere.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein the T_(om) of said particles introducedinto said annealing zone is at least 10° C. lower than the T_(om) ofsaid particles produced from said annealing zone.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein said particles produced from saidannealing zone have a degree of crystallinity less than 42 percent.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein said crystallizing takes place at apressure of less than 10 psig.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein said crystallizing does not includethermal crystallization.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein said particles produced from saidcrystallizing zone have an average bulk temperature that is at least 5°C. higher than the average bulk temperature of said particles introducedinto said crystallizing zone.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein said particles have an average residencetime in said crystallizing zone of less than 20 minutes.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein the average bulk temperature of saidparticles produced from said annealing zone is lower than the averagebulk temperature of said particles introduced into said annealing zone.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein the average bulk temperature of saidparticles produced from said annealing zone is in the range of fromabout 0.5° C. to about 10° C. lower than the average bulk temperature ofsaid particles introduced into said annealing zone.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein said particles have an average residencetime in said drying zone of less than 1 minute.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein said drying zone is at least partiallydefined in a centrifugal-type dryer.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein at least a portion of said crystallizingzone is defined in a mechanically agitated crystallizer.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein at least a portion of said crystallizingzone is defined in a mechanically agitated crystallizer. Saidcrystallizer may be a shaker deck crystallizer.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein said particles have a residence time insaid annealing zone of between 1 hour and 24 hours, 4 hours and 24hours, or 8 hours and 24 hours.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein said particles produced from saidannealing zone comprise a shell and a core, wherein said shellsubstantially surrounds said core, wherein at least a portion of saidcore was formed via spherulitic crystallization, wherein at least aportion of said shell was formed via strain-induced crystallization.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein said particles produced from saidannealing zone have a spheroidal shape.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein said particles produced from saidannealing zone comprise less than 8 ppm of antimony catalyst.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein said polyester polymer production processis not a solid-stating process.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein the total thermal energy added to saidpolyester polymer production process between steps (a) and (d) is lessthan 100 BTU/lb of said particles produced from said annealing zone.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein said polyester polymer melt comprises acarboxylic aid component and a hydroxyl component, wherein saidcarboxylic acid component comprises at least 80 mole percent of theresidues of terephthalic acid and/or derivatives thereof, wherein saidhydroxyl component comprises at least 80 mole percent of residues ofethylene glycol.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein said particles produced from saidannealing zone, when measured on a first heating DSC scan, have aonset-of-melt temperature greater than 165° C., and a melting endothermarea greater the absolute value of 1 J/g, 2 J/g, 4 J/g, 8 J/g, or 16J/g.

The process of Embodiment A or Embodiment A with any one or more of theintervening features, wherein the low melting peak temperature of saidparticles introduced into said annealing zone is at least 10° C. lowerthan the low melting peak temperature of said particles produced fromsaid annealing zone.

In Embodiment B of the present invention, there is provided a polyesterpolymer production process comprising: (a) forming initial polyesterpolymer particles from a polymer melt having an intrinsic viscosity(It.V.) in the range of 0.70 dL/g to 1.2 dL/g, 0.70 dL/g to 1.1 dL/g,0.72 dL/g to 1.2 dL/g, 0.72 dL/g to 1.1 dL/g, 0.76 dL/g to 1.2 dL/g,0.76 dL/g to 1.1 dL/g, 0.78 dL/g to 1.2 dL/g, or 0.78 dL/g to 1.0 dL/g,wherein the initial particles comprise a shell and a core, wherein theshell is cooler and more crystalline than the core, wherein at least aportion of the shell exhibits strain-induced crystallinity; (b) dryingat least a portion of the initial particles to thereby provide driedparticles; (c) crystallizing at least a portion of the dried particlesto thereby provide crystallized particles exhibiting both strain-inducedcrystallinity and spherulitic crystallinity; and (d) annealing at leasta portion of the crystallized particles to thereby provide annealedparticles, wherein the average bulk temperature of the initial particlesand the dried particles is maintained above the onset-of-meltingtemperature (T_(om)) of the core.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, wherein the average bulk temperature of saidinitial particles, said dried particles, and said crystallized particlesis maintained at a temperature greater than 165° C.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, wherein said particles produced from saidannealing zone, when measured on a first heating DSC scan, have a lowmelting peak temperature greater than 190° C., and a melting endothermarea greater than the absolute value of 1 J/g, 2 J/g, 4 J/g, 8 J/g, or16 J/g.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, wherein the It.V. of said initial particles iswithin about 5 percent of the It.V. of said annealed particles.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, further comprising, prior to step (b), quenchingat least a portion of said initial particles via contact with a quenchliquid to thereby provide quenched particles, wherein said initialparticles dried in step (b) comprise at least a portion of said quenchedparticles.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, further comprising, prior to step (b), quenchingat least a portion of said initial particles via contact with a quenchliquid to thereby provide quenched particles, wherein said initialparticles dried in step (b) comprise at least a portion of said quenchedparticles and wherein said quenching is carried out in less than 30seconds.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, further comprising, prior to step (b), quenchingat least a portion of said initial particles via contact with a quenchliquid to thereby provide quenched particles, wherein said initialparticles dried in step (b) comprise at least a portion of said quenchedparticles and wherein said quenching includes contacting said initialparticles with said quench liquid in a quench vessel to thereby form aslurry, wherein said quenching includes transporting said slurry fromsaid quench vessel to a drying zone via a slurry conduit, wherein theflow velocity of said slurry in said slurry conduit is greater thanabout 10 feet per second.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, further comprising, prior to step (b), quenchingat least a portion of said initial particles via contact with a quenchliquid to thereby provide quenched particles, wherein said initialparticles dried in step (b) comprise at least a portion of said quenchedparticles and wherein said quenching includes contacting said initialparticles with said quench liquid in a quench vessel to thereby form aslurry, wherein said quenching includes transporting said slurry fromsaid quench vessel to a drying zone via a slurry conduit, wherein theflow velocity of said slurry in said slurry conduit is greater thanabout 10 feet per second and wherein said slurry conduit has an overallflow path length less than 50 feet.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, wherein said crystallization is carried out at apressure of less than 10 psig.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, wherein said crystallized particles have anaverage bulk temperature greater than 180° C.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, wherein said crystallizing is carried out in agas-phase latent heat crystallizer.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, wherein said crystallizing does not includethermal crystallization.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, wherein said crystallized particles exiting saidcrystallizing zone have an average bulk temperature that is at least 5°C. higher than said dried particles entering said crystallizing zone.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, wherein said particles have an average residencetime in said crystallizing zone of less than 20 minutes.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, wherein said annealed particles have an averagebulk temperature that is in the range of from about 0.5° C. to about 10°C. less than the average bulk temperature of said crystallizedparticles.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, wherein said annealed particles comprise less than8 ppm of antimony catalyst.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, wherein said annealed particles have a T_(om) thatis at least 5° C. higher than the T_(om) of said crystallized particles.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, wherein said annealed particles have a degree ofcrystallinity in the range of from about 34 to about 42 percent.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, wherein said shell substantially surrounds saidcore, wherein at least a portion of said initial particles arespheroidal.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, wherein said polymer melt comprises a carboxylicacid component and a hydroxyl component, wherein said carboxylic acidcomponent comprises at least 80 mole percent of the residues ofterephthalic acid and/or derivatives thereof, wherein said hydroxylcomponent comprises at least 80 mole percent of residues of ethyleneglycol.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, wherein the total thermal energy added to saidpolyester polymer production process between steps (a) and (d) is lessthan 100 BTU/pound of said anneal particles.

The process of Embodiment B or Embodiment B with any one or more of theintervening features, wherein said particles produced from saidannealing zone, when measured on a first heating DSC scan, have aonset-of-melt temperature greater than 165° C., and a melting endothermarea greater the absolute value of 1 J/g, 2 J/g, 4 J/g, 8 J/g, or 16J/g.

In Embodiment C of the present invention, there is provided a polyesterpolymer production process comprising: (a) forming initial polyesterpolymer particles from a polymer melt having an intrinsic viscosity(It.V.) in the range of 0.70 dL/g to 1.2 dL/g, 0.70 dL/g to 1.1 dL/g,0.72 dL/g to 1.2 dL/g, 0.72 dL/g to 1.1 dL/g, 0.76 dL/g to 1.2 dL/g,0.76 dL/g to 1.1 dL/g, 0.78 dL/g to 1.2 dL/g, or 0.78 dL/g to 1.0 dL/g;(b) crystallizing at least a portion of the initial particles in agas-atmosphere latent heat crystallizer to thereby provide crystallizedparticles, wherein the average bulk temperature of the crystallizedparticles exiting the latent heat crystallizer is greater than 185° C.;and (c) cooling at least a portion of the crystallized particles tothereby provide cooled particles, wherein the cooled particles have anonset-of-melting temperature (T_(om)) greater than 210° C., wherein thecooled particles exhibit only one melt peak having a melting endothermarea greater the absolute value of 1 J/g, 2 J/g, 4 J/g, 8 J/g, or 16 J/gwhen measured on a DSC first heating scan, wherein the one melt peak hasa peak temperature greater than 190° C., wherein the cooled particleshave a degree of crystallinity less than 42 percent.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, further comprising, prior to cooling saidcrystallized particles, annealing at least a portion of saidcrystallized particles to thereby provide annealed particles, wherein atleast a portion of said crystallized particles cooled in step (c)comprise at least a portion of said annealed particles.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein said annealing causes the T_(om) of saidcrystallized particles to increase by at least 5° C.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein the average bulk temperature of saidannealed particles is lower than the average bulk temperature of saidcrystallized particles.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein said annealing is carried out for between1 hour and 24 hours, 4 hours and 24 hours, or 8 hours and 24 hours.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein the average bulk temperature of theinitial particles is maintained at a temperature greater than about 165°C. during steps (a) and (b).

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein said cooled particles have an It.V. withinabout 5 percent of the It.V. of said polymer melt.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein said crystallizing is carried out at apressure less than about 15 psig.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein said forming of step (a) comprisespelletizing said polymer melt to thereby form said initial particles,and, simultaneously with said pelletizing, contacting at least a portionof said initial particles with a quench liquid to thereby form quenchedinitial particles.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein said quenched initial particles comprise ashell and a core, wherein said shell is cooler and more crystalline thansaid core, wherein at least a portion of said shell exhibitsstrain-induced crystallinity

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein said shell substantially surrounds saidcore.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein at least a portion of said core of saidcrystallized particles exhibit spherulitic crystallinity.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, further comprising, drying at least a portion ofsaid quenched initial particles to thereby provide dried initialparticles.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein step (a) is carried out in less than 30seconds.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein said crystallizing is carried out for lessthan 20 minutes.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein said crystallizing does not comprisethermal crystallization.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein the average bulk temperature of saidinitial particles entering said crystallizer is at least about 10° C.cooler than the average bulk temperature of said crystallized particlesexiting said crystallizer.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein said crystallizer is a shaker deckcrystallizer.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein said cooled particles comprise less than10 ppm of antimony catalysts.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein said cooled particles have a degree ofcrystallinity in the range of from about 34 percent to about 42 percent.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein said melting peak temperature is greaterthan 235° C.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein said polymer melt comprises a carboxylicacid component and a hydroxyl component, wherein said carboxylic acidcomponent comprises at least 80 mole percent of the residues ofterephthalic acid and/or derivatives thereof, wherein said hydroxylcomponent comprises at least 80 mole percent of residues of ethyleneglycol.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein said polymer melt comprises at least 75percent virgin polymer.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein the total thermal energy added to saidprocess during steps (a) through (c) is less than 100 BTU/lb of saidcrystallized particles.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein said annealed particles, when measured ona first heating DSC scan, have an onset-of-melt temperature greater than165° C., and a melting endotherm area greater the absolute value of 1J/g, 2 J/g, 4 J/g, 8 J/g, or 16 J/g.

The process of Embodiment C or Embodiment C with any one or more of theintervening features, wherein the low melting peak temperature of saidcrystallized particles is at least 10° C. lower than the low meltingpeak temperature of said annealed particles.

In Embodiment D of the present invention, there is provided a polyesterpolymer production process comprising: (a) forming initial polyesterpolymer particles from a polymer melt; (b) immersing at least a portionof the initial particles in a quench liquid to thereby form a particleslurry; (c) separating a substantial portion of the quench liquid fromthe initial particles to thereby provided dried particles; (d)crystallizing at least a portion of the dried particles in acrystallizer to thereby provide crystallized particles, wherein theaverage bulk temperature of the crystallized particles exiting thecrystallizer is at least 185° C.; (e) annealing at least a portion ofthe crystallized particles to thereby provide annealed particles; and(f) cooling at least a portion of the annealed particles to therebyprovide cooled particles, wherein the cooled particles have an intrinsicviscosity (It.V.) within 5 percent of the It.V. of the polyester polymermelt.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein said cooled particles when measured on afirst heating DSC scan, have a low melting peak temperature greater than190° C., and a melting endotherm area greater the absolute value of 1J/g, 2 J/g, 4 J/g, 8 J/g, or 16 J/g.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein said cooled particles have a T_(om) of atleast about 165° C.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein said polymer melt has an It.V. in therange of 0.70 dL/g to 1.2 dL/g, 0.70 dL/g to 1.1 dL/g, 0.72 dL/g to 1.2dL/g, 0.72 dL/g to 1.1 dL/g, 0.76 dL/g to 1.2 dL/g, 0.76 dL/g to 1.1dL/g, 0.78 dL/g to 1.2 dL/g, or 0.78 dL/g to 1.0 dL/g.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein steps (b) and (c) can be carried out in aperiod of time less than about 30 seconds.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein the average bulk temperature of saidinitial particles and said dried particles is maintained above 165° C.at all points during steps (a)-(c).

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein said crystallizing is carried out for lessthan 30 minutes.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein said crystallizer is a gas-atmospherelatent heat crystallizer.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein said crystallizer is a shaker deckcrystallizer.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein said crystallizing is carried out at apressure of less than 15 psig.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein the average bulk temperature of saidcrystallized particles is at least 10° C. greater than the average bulktemperature of said annealed particles.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein said annealed particles have a T_(om) atleast about 10° C. higher than the T_(om) of said crystallizedparticles.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein said cooled particles have a degree ofcrystallinity less than 42 percent.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein said cooled particles comprise a shell anda core, wherein said shell substantially surrounds said core, wherein atleast a portion of said shell exhibits strain-induced crystallinity,wherein at least a portion of said core exhibits spheruliticcrystallinity.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein at least a portion of said cooledparticles are spheroidal particles.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein said cooled particles comprise less than10 ppmw of antimony catalysts.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein said slurry flows through a slurryconduit, wherein the flow velocity of said slurry in said slurry conduitis greater than 10 feet per second.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein said slurry conduit has an overall flowpath length less than 25 feet.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein at least a portion of said separating iscarried out in a centrifugal dryer, wherein said particles have anaverage residence time in said dryer of less than 30 seconds.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein said annealing is carried out for between1 hour and 24 hours, 4 hours and 24 hours, or 8 hours and 24 hours.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein said polymer melt comprises a carboxylicacid component and a hydroxyl component, wherein said carboxylic acidcomponent comprises at least 80 mole percent of the residues ofterephthalic acid and/or derivatives thereof, wherein said hydroxylcomponent comprises at least 80 mole percent of residues of ethyleneglycol.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein the total thermal energy added to saidprocess during steps (a) through (f) is less than 100 BTU/lb of saidcooled particles.

The process of Embodiment D or Embodiment D with any one or more of theintervening features, wherein said annealed particles, when measured ona first heating DSC scan, have a onset-of-melt temperature greater than165° C., and a melting endotherm area greater the absolute value of 1J/g, 2 J/g, 4 J/g, 8 J/g, or 16 J/g.

In Embodiment E of the present invention, there is provided a polyesterpolymer production process comprising: (a) transporting a slurrycomprising polyester polymer particles and a liquid through a slurryconduit coupled to a centrifugal particle dryer, wherein the dryercomprises a housing, a generally cylindrical screen located inside thehousing, and a generally upright rotor configured to rotate inside thescreen; (b) discharging the slurry through an inlet opening of thescreen in a discharge direction offset from the axis of rotation of therotor, wherein the discharge direction is generally in the direction ofrotation of the rotor at the inlet opening; and (c) removing the quenchliquid from the polymer particles in the particle dryer to therebyproduce dried polyester polymer particles.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said discharge direction is generallytangential to said screen.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said slurry is discharged into said dryerat a slurry discharge speed, wherein said slurry discharge speed is lessthan 75 percent of the tip speed of said upright rotor.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein the rotational speed of said upright rotoris at least 850 revolutions per minute.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein the flow velocity of said slurry in saidslurry conduit is greater than 10 feet per second.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said slurry conduit defines an overallflow path that is less than 50 feet long.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said slurry conduit further comprises aparticle filter fluidly disposed upstream of said centrifugal dryer,wherein said particle filter is operable to trap agglomerated chunks ofsaid polyester polymer particles.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said slurry is passed through saidparticle filter in a generally upward direction.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said slurry is pumped through saidparticle filter.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said slurry conduit further comprises aliquid removal device, wherein said liquid removal device is operable toseparate at least 50 weight percent of the total liquid from said slurryto thereby provide a concentrated slurry.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said concentrated slurry has a solidscontent in the range of from about 25 to about 99 weight percent solids.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said quench liquid comprises water.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said slurry has a solids content in therange of from about 2 to about 50 weight percent.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said polyester polymer particles have anaverage size in the range of from about 1 to about 8 millimeters.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said quench liquid has an averagetemperature in the range of from about 80° C. to about 110° C.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said dryer defines a maximum horizontaldimension (D) and a maximum vertical dimension (H), wherein said dryerhas a H:D ratio in the range of from about 1.5:1 to about 20:1.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein H is in the range of from about 0.5 feetto about 100 feet, wherein D is in the range of from about 0.25 feet toabout 80 feet.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said dryer has a liquid removal efficiencygreater than about 75 percent.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said polyester polymer particles travelgenerally upwardly through said dryer during said removing of step (c).

The process of Embodiment E or Embodiment E with any one or more of theintervening features, further comprising crystallizing at least aportion of said dried particles in a latent heat crystallizer to therebyprovide crystallized particles, wherein said dried particles enteringsaid latent heat crystallizer have an average bulk temperature in therange of from about 170° C. to about 210° C., wherein said particleshave an average residence time in said crystallizer of less than 30minutes.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said crystallizing is carried out at apressure less than 15 psig.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said crystallizer is a shaker deckcrystallizer.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, further comprising annealing at least a portion ofsaid crystallized particles to thereby provide annealed particles.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said annealing causes the onset-of-meltingtemperature (T_(om)) of said crystallized particles to increase by atleast 5° C., wherein the average bulk temperature of said annealedparticles is at least 5° C. cooler than the average bulk temperature ofsaid crystallized particles.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said annealed particles when measured on afirst heating DSC scan, have a low melting peak temperature greater than190° C., and a melting endotherm area greater the absolute value of 1J/g, 2 J/g, 4 J/g, 8 J/g, or 16 J/g.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said polyester polymer particles comprisea carboxylic acid component and a hydroxyl component, wherein saidcarboxylic acid component comprises at least 80 mole percent of theresidues of terephthalic acid and/or derivatives thereof, wherein saidhydroxyl component comprises at least 80 mole percent of residues ofethylene glycol.

The process of Embodiment E or Embodiment E with any one or more of theintervening features, wherein said annealed particles, when measured ona first heating DSC scan, have a onset-of-melt temperature greater than165° C., and a melting endotherm area greater the absolute value of 1J/g, 2 J/g, 4 J/g, 8 J/g, or 16 J/g.

In Embodiment F of the present invention, there is provided an apparatusfor producing polyester polymer particles from a polyester melt. Theapparatus comprises a cutter for cutting the polymer melt intoparticles, a quench zone for contacting the particles with a quenchliquid, a dryer for removing the quench liquid from the particles, and aslurry conduit providing fluid flow communication between the quenchzone and the dryer. The dryer is a centrifugal particle dryer comprisinga housing, a generally cylindrical screen located in the housing, and agenerally upright rotor configured to rotate inside the screen. Thescreen defines an inlet opening and the slurry conduit comprises adischarge section configured to discharge the slurry through the inletopening. The slurry can be discharged in a discharge direction offsetfrom the axis of rotation of the upright rotor in a direction that isgenerally in the direction of rotation of the rotor at the inletopening.

The apparatus of Embodiment F or Embodiment F with any one or more ofthe intervening features, wherein said dryer further comprises a removedliquid conduit operable to withdraw at least a portion of the quenchliquid removed from said particles, wherein said removed liquid conduitprovides fluid flow communication between said dryer and said quenchzone.

The apparatus of Embodiment F or Embodiment F with any one or more ofthe intervening features, further comprising a particle filter locatedupstream of said dryer and fluidly disposed in said slurry conduit,wherein said particle filter is operable to trap agglomerated chunks ofsaid particles.

The apparatus of Embodiment F or Embodiment F with any one or more ofthe intervening features, wherein said particle filter defines a slurryinlet and a slurry outlet, wherein said slurry outlet is located at ahigher vertical elevation than said slurry inlet.

The apparatus of Embodiment F or Embodiment F with any one or more ofthe intervening features, further comprising a quench liquid removaldevice fluidly disposed in said slurry conduit upstream of said dryer,wherein said quench liquid removal device comprises a liquid outlet.

The apparatus of Embodiment F or Embodiment F with any one or more ofthe intervening features, wherein said quench liquid removal devicecomprises an angularly oriented screen.

The apparatus of Embodiment F or Embodiment F with any one or more ofthe intervening features, wherein said dryer further comprises a driedparticle outlet, wherein said dried particle outlet is positioned at ahigher vertical elevation than said inlet opening of said screen.

The apparatus of Embodiment F or Embodiment F with any one or more ofthe intervening features, further comprising a latent heat crystallizerdefining a dried particle inlet and a crystallized particle outlet,wherein said dried particle outlet of said dryer is in fluid flowcommunication with said dried particle inlet of said crystallizer.

The apparatus of Embodiment F or Embodiment F with any one or more ofthe intervening features, wherein said crystallizer comprises a shakerdeck crystallizer.

The apparatus of Embodiment F or Embodiment F with any one or more ofthe intervening features, further comprising an annealer defining acrystallized particle inlet and an annealed particle outlet, whereinsaid crystallized particle outlet of said crystallizer is in fluid flowcommunication with said crystallized particle inlet of said annealer.

The apparatus of Embodiment F or Embodiment F with any one or more ofthe intervening features, wherein said dryer defines a maximumhorizontal dimension (D) and a maximum vertical dimension (H), whereinsaid dryer has a H:D ratio in the range of from about 1.5:1 to about20:1.

The apparatus of Embodiment F or Embodiment F with any one or more ofthe intervening features, wherein H is in the range of from about 0.5feet to about 100 feet, wherein D is in the range of from about 0.25feet to about 80 feet.

In Embodiment G of the present invention, there is provided a polyesterpolymer production process comprising: (a) forming initial polyesterpolymer particles from a polymer melt; (b) immersing at least a portionof the initial particles in a quench liquid to thereby provide aparticle slurry; (c) separating a substantial portion of the quenchliquid from the initial particles to thereby provide dried particles andseparated quench liquid; (d) crystallizing at least a portion of thedried particles to thereby provide crystallized particles; (e) measuringa downstream temperature of the dried particles and/or the crystallizedparticles; and (f) adjusting the time that the initial particles areimmersed in the quench liquid based on the downstream temperature.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, further comprising, subsequent to said measuringof step (e), comparing said downstream temperature to a targettemperature to determine a difference, wherein said adjusting of step(f) is carried out based on said difference.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein said target temperature corresponds to aparticle average bulk temperature in the range of from 165° C. to 215°C.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, further comprising repeating said measuring,comparing, and adjusting until said difference is less than 10 percentof said target temperature.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein at least a portion of said measuring,comparing, and/or adjusting is carried out by an automated controlsystem.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein said adjusting of step (f) includeschanging the volumetric flow rate of said quench liquid used to formsaid particle slurry of step (b).

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein said initial particles are immersed insaid quench liquid for less than 30 seconds.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, further comprising transporting said particleslurry to a dryer via a slurry conduit, wherein at least a portion ofsaid separating of step (c) is carried out in said dryer.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein said particle slurry in said slurryconduit has an average flow velocity greater than 10 feet per second.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein said transporting includes pumping saidparticle slurry through said slurry conduit into said dryer.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein said dryer is a centrifugal dryer, whereinsaid particle slurry is tangentially introduced into said dryer.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, further comprising, subsequent to step (d),annealing at least a portion of said crystallized particles to therebyprovide annealed particles.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein at least a portion of said crystallizingis carried out in a crystallizer, wherein at least a portion of saidannealing is carried out in an annealer, wherein said downstreamtemperature is measured at a location downstream of said crystallizerand upstream of said annealer.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein said crystallizer is a shaker deckcrystallizer.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein said annealing increases theonset-of-melting temperature (T_(om)) of said crystallized particles byat least 10° C.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein said annealing decreases the average bulktemperature of said crystallized particles by an amount in the range offrom 0.5° C. to 10° C.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein said annealed particles comprise a shelland a core, wherein said shell substantially surrounds said core,wherein at least a portion of said core was formed via spheruliticcrystallization, wherein at least a portion of said shell was formed viastrain-induced crystallization, wherein at least a portion of saidannealed particles have a spheroidal shape.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein at least a portion of said crystallizingof step (d) is carried out in a gas-phase atmosphere latent heatcrystallizer, wherein said crystallized particles have an average bulktemperature that is at least about 5° C. higher than said driedparticles.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein said crystallized particles have anaverage bulk temperature that is at least about 10° C. higher than saiddried particles.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein said crystallizing of step (d) is carriedout at a pressure of less than 10 psig.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein said crystallized particles have anaverage bulk temperature greater than 180° C.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein the average bulk temperature of theparticles processed in steps (a) through (d) is maintained at atemperature greater than 160° C. at all points during steps (a) through(d).

The process of Embodiment G or Embodiment G with any one or more of theintervening features, further comprising, subsequent to saidcrystallizing of step (d), cooling at least a portion of saidcrystallized particles to thereby provide cooled particles having anaverage bulk temperature below 100° C.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein the intrinsic viscosity (It.V.) of saidinitial particles is within about 5 percent of the It.V. of said cooledparticles.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein said cooled particles, when measured on afirst heating DSC scan, have a low melting peak temperature greater than190° C., and a melting endotherm area greater the absolute value of 1J/g, 2 J/g, 4 J/g, 8 J/g, or 16 J/g.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein said cooled particles comprise less than 8ppm of antimony catalyst.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein said cooled particles have a degree ofcrystallinity of less than 42 percent.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein said polymer melt has an intrinsicviscosity in the range of 0.70 dL/g to 1.2 dL/g, 0.70 dL/g to 1.1 dL/g,0.72 dL/g to 1.2 dL/g, 0.72 dL/g to 1.1 dL/g, 0.76 dL/g to 1.2 dL/g,0.76 dL/g to 1.1 dL/g, 0.78 dL/g to 1.2 dL/g, or 0.78 dL/g to 1.0 dL/g.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein said polymer melt comprises a carboxylicacid component and a hydroxyl component, wherein said carboxylic acidcomponent comprises at least 80 mole percent of the residues ofterephthalic acid and/or derivatives thereof, wherein said hydroxylcomponent comprises at least 80 mole percent of residues of ethyleneglycol.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein the total thermal energy added to saidprocess during steps (a) through (d) is less than 100 BTU/lb of saidcrystallized particles.

The process of Embodiment G or Embodiment G with any one or more of theintervening features, wherein said polyester polymer production processis not a solid-stating process.

In Embodiment H of the present invention, there is provided a polyesterpolymer production process comprising: (a) forming polyester polymerparticles from a polyester polymer melt; (b) subsequent to step (a),transporting a slurry comprising at least a portion of the particles anda quench liquid through a conduit; (c) subsequent to step (b),introducing at least a portion of the slurry into a dryer; (d)subsequent to step (c), substantially separating the particles and thequench liquid in the dryer to thereby provide dried particles; (e)subsequent to step (d), crystallizing at least a portion of the driedparticles to thereby provide crystallized particles; (f) subsequent tostep (e), annealing at least a portion of the crystallized particles tothereby provide annealed particles; (g) subsequent to step (f), coolingat least a portion of the annealed particles to thereby provide cooledparticles; (h) measuring a downstream temperature of the particles at alocation downstream of the dryer and upstream of the annealer; and (i)adjusting the flow rate of the quench liquid though the conduit based onthe downstream temperature.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein said slurry has a solids content in therange of from about 2 to about 50 weight percent.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein the average flow velocity of said slurryin said conduit is greater than 10 feet per second.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein said transporting of step (a) includespumping said slurry through said conduit.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein said transporting of step (a) furthercomprises passing at least a portion of said slurry through a particlefilter, wherein said particle filter is operable to trap agglomeratedchunks of said polyester polymer particles.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein said passing of said slurry through saidparticle filter is carried out in a generally upward direction.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein said particles entering said dryer in saidslurry have an average size in the range of from about 1 to about 8millimeters.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein said separating of step (d) includesseparating at least 85 percent of said quench liquid from saidparticles.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein at least a portion of said crystallizingof step (e) is carried out in a gas-phase atmosphere latent heatcrystallizer, wherein said crystallized particles have an average bulktemperature that is at least about 10° C. higher than said driedparticles.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein said crystallizer is a shaker deckcrystallizer.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein said crystallized particles have anaverage bulk temperature greater than 180° C.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein said crystallizing is carried out at apressure of less than 10 psig.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein said annealing increases theonset-of-melting temperature (T_(om)) of said crystallized particles byat least 10° C.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein said annealing decreases the average bulktemperature of said crystallized particles by an amount in the range offrom about 0.5° C. to about 10° C.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein said annealed particles comprise a shelland a core, wherein said shell substantially surrounds said core,wherein at least a portion of said core was formed via spheruliticcrystallization, wherein at least a portion of said shell was formed viastrain-induced crystallization, wherein at least a portion of saidannealed particles have a spheroidal shape.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein said polyester polymer particles areimmersed in said quench liquid for less than 30 seconds.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein the average bulk temperature of theparticles processed in steps (a) through (f) is maintained at atemperature greater than 165° C. at all points during steps (a) through(f).

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein the intrinsic viscosity (It.V.) of saidparticles formed in step (a) is within about 5 percent of the It.V. ofsaid cooled particles.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein said cooled particles, when measured on afirst heating DSC scan, have a low melting peak temperature greater than190° C., and a melting endotherm area greater the absolute value of 1J/g, 2 J/g, 4 J/g, 8 J/g, or 16 J/g.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein said cooled particles have a degree ofcrystallinity less than 42 percent.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein said polymer melt has an It.V. in therange of 0.70 dL/g to 1.2 dL/g, 0.70 dL/g to 1.1 dL/g, 0.72 dL/g to 1.2dL/g, 0.72 dL/g to 1.1 dL/g, 0.76 dL/g to 1.2 dL/g, 0.76 dL/g to 1.1dL/g, 0.78 dL/g to 1.2 dL/g, or 0.78 dL/g to 1.0 dL/g.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein said polymer melt comprises a carboxylicacid component and a hydroxyl component, wherein said carboxylic acidcomponent comprises at least 80 mole percent of the residues ofterephthalic acid and/or derivatives thereof, wherein said hydroxylcomponent comprises at least 80 mole percent of residues of ethyleneglycol.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein the total thermal energy added to saidprocess during steps (a) through (g) is less than 100 BTU/lb of saidcooled particles.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein said cooled particles, when measured on afirst heating DSC scan, have a onset-of-melt temperature greater than165° C., and a melting endotherm area greater the absolute value of 1J/g, 2 J/g, 4 J/g, 8 J/g, or 16 J/g.

The process of Embodiment H or Embodiment H with any one or more of theintervening features, wherein said cooled particles, when measured on afirst heating DSC scan, have a onset-of-melt temperature greater than165° C., and a melting endotherm area greater the absolute value of 1J/g, 2 J/g, 4 J/g, 8 J/g, or 16 J/g.

In Embodiment J of the present invention, there is provided a bulk ofpolyethylene terephthalate (PET) particles, wherein the PET particleshave the following characteristics: (a) the particles comprise a shelland a core, wherein the shell substantially surrounds the core, whereinat least a portion of the shell exhibits strain-induced crystallinityand at least a portion of the core exhibits spherulitic crystallinity;(b) when measured on a first heating DSC scan, the particles have a lowmelting peak temperature greater than 200° C.; and a melting endothermarea greater than the absolute value of 1 J/g, 2 J/g, 4 J/g, 8 J/g, or16 J/g, and (c) the particles have a degree of crystallinity less than44 percent.

The particles of Embodiment J or Embodiment J with any one or more ofthe intervening features, wherein at least a portion of said particlesare spheroidal.

The particles of Embodiment J or Embodiment J with any one or more ofthe intervening features, having a onset-of-melt temperature (T_(om))greater than 165° C. or 175° C.

The particles of Embodiment J or Embodiment J with any one or more ofthe intervening features, wherein said particles comprise less than 10ppmw of antimony catalyst.

The particles of Embodiment J or Embodiment J with any one or more ofthe intervening features, wherein said particles comprise less than 100ppm of one or more acetaldehyde scavengers.

The particles of Embodiment J or Embodiment J with any one or more ofthe intervening features, wherein said particles are substantially freeof one or more acetaldehyde scavengers.

The particles of Embodiment J or Embodiment J with any one or more ofthe intervening features, wherein said particles have an onset-of-melttemperature of greater than 175° C.

The particles of Embodiment J or Embodiment J with any one or more ofthe intervening features, wherein said particles have an intrinsicviscosity (It.V.) in the range of 0.70 dL/g to 1.2 dL/g, 0.70 dL/g to1.1 dL/g, 0.72 dL/g to 1.2 dL/g, 0.72 dL/g to 1.1 dL/g, 0.76 dL/g to 1.2dL/g, 0.76 dL/g to 1.1 dL/g, 0.78 dL/g to 1.2 dL/g, or 0.78 dL/g to 1.0dL/g.

In Embodiment K of the present invention, there is provided a bulk ofpolyethylene terephthalate (PET) particles, wherein the PET particleshave the following characteristics: (a) the particles comprise a shelland a core, wherein the shell substantially surrounds the core, whereinat least a portion of the shell exhibits strain-induced crystallinityand at least a portion of the core exhibits spherulitic crystallinity;(b) when measured on a first heating DSC scan, the particles have anonset-of-melting temperature greater than 180° C.; and a meltingendotherm area greater than the absolute value of 1 J/g, 2 J/g, 4 J/g, 8J/g, or 16 J/g., and (c) the particles have a degree of crystallinityless than 44 percent.

The particles of Embodiment K or Embodiment K with any one or more ofthe intervening features, wherein at least a portion of said particlesare spheroidal.

The particles of Embodiment K or Embodiment K with any one or more ofthe intervening features, having a low melting peak temperature greaterthan 195° C.

The particles of Embodiment K or Embodiment K with any one or more ofthe intervening features, wherein said particles comprise less than 10ppmw of antimony catalyst.

The particles of Embodiment K or Embodiment K with any one or more ofthe intervening features, wherein said particles comprise less than 100ppm of one or more acetaldehyde scavengers.

The particles of Embodiment K or Embodiment K with any one or more ofthe intervening features, wherein said particles are substantially freeof one or more acetaldehyde scavengers.

The particles of Embodiment K or Embodiment K with any one or more ofthe intervening features, having an intrinsic viscosity (It.V.) in therange of 0.70 dL/g to 1.2 dL/g, 0.70 dL/g to 1.1 dL/g, 0.72 dig to 1.2dL/g, 0.72 dig to 1.1 dL/g, 0.76 dL/g to 1.2 dL/g, 0.76 dL/g to 1.1dL/g, 0.78 dL/g to 1.2 dL/g, or 0.78 dL/g to 1.0 dL/g.

Claims not Limited to Disclosed Embodiments

The preferred forms of the invention described above are to be used asillustration only, and should not be used in a limiting sense tointerpret the scope of the present invention. Modifications to theexemplary embodiments, set forth above, could be readily made by thoseskilled in the art without departing from the spirit of the presentinvention.

The inventors hereby state their intent to rely on the Doctrine ofEquivalents to determine and assess the reasonably fair scope of thepresent invention as pertains to any apparatus not materially departingfrom but outside the literal scope of the invention as set forth in thefollowing claims.

1. A bulk of polyethylene terephthalate (PET) particles, wherein saidPET particles have the following characteristics: (a) comprise a shelland a core, wherein said shell substantially surrounds said core,wherein at least a portion of said shell exhibits strain-inducedcrystallinity and at least a portion of said core exhibits spheruliticcrystallinity; (b) when measured on a first heating DSC scan, saidparticles have a low melting peak temperature greater than 190° C., anda melting endotherm area greater than the absolute value of 1 J/g; and(c) a degree of crystallinity less than 44 percent.
 2. The particles ofclaim 1, wherein at least a portion of said particles are spheroidal. 3.The particles of claim 1, having an onset-of-melt temperature (T_(om))greater than 175° C.
 4. The particles of claim 1, wherein said particlescomprise less than 10 ppmw of antimony catalyst.
 5. The particles ofclaim 1, wherein said particles comprise less than 100 ppmw of one ormore acetaldehyde scavengers.
 6. The particles of claim 5, wherein saidparticles are substantially free of one or more acetaldehyde scavengers.7. The particles of claim 1, having an onset-of-melt temperature ofgreater than 175° C.
 8. The particles of claim 1, having an intrinsicviscosity (It.V.) of at least 0.70 dL/g.
 9. A bulk of polyethyleneterephthalate (PET) particles, wherein said PET particles have thefollowing characteristics: (a) comprise a shell and a core, wherein saidshell substantially surrounds said core, wherein at least a portion ofsaid shell exhibits strain-induced crystallinity and at least a portionof said core exhibits spherulitic crystallinity; (b) when measured on afirst heating DSC scan, said particles have an onset-of-meltingtemperature greater than 180° C. and a melting endotherm area greaterthan the absolute value of 1 J/g; and (c) a degree of crystallinity lessthan 44 percent.
 10. The particles of claim 9, wherein at least aportion of said particles are spheroidal.
 11. The particles of claim 9,having a low melting peak temperature greater than 195° C.
 12. Theparticles of claim 9, wherein said particles comprise less than 10 ppmwof antimony catalyst.
 13. The particles of claim 9, wherein saidparticles comprise less than 100 ppmw of one or more acetaldehydescavengers.
 14. The particles of claim 13, wherein said particles aresubstantially free of one or more acetaldehyde scavengers.
 15. Theparticles of claim 9, having an intrinsic viscosity (It.V.) of at least0.70 dL/g.